As the trope namer is one of the most blatant examples, myriad justifications have been offered over the years.
One nobody seems to say aloud is that the comic is virtually a love letter from Clark Kent to Lois Lane. Lois Lane can never fall in love with the boring loser like Clark Kent, so she will never realize he is Superman.
In earlier Superman comics, he had minor Shapeshifting abilities that allowed him to look ever so slightly different as Clark Kent. This was attributed to his fantastic "facial muscle control", a Hand Wave previously used by several Pulp Magazine heroes to explain their Master of Disguise ability without making them seem too unmanly by wearing makeup. This explanation vanished as the trope fell out of use.
Other versions have stated that he at least avoids being recognized from photographs by vibrating slightly to mess with the details.
Most Superman canon, from the 1970s to the current batch of comics, puts forth that the disguise is in a great deal of things that simply aren't conveyed on a comics page, and that he uses utterly different body language, mannerisms, and tones of voice as Clark Kent, making his acquaintances think he was just some guy who kind of looked like Superman. Grant Morrison's All-Star Superman runs with this to great effect (at one point, being too sick to effect his disguise, he actually pulls off "Superman was disguised as Clark") and anyone who watched Christopher Reeve in the movies knows it can be effective. When a master actor like Reeve plays the identities, the disguise feels much more believable. He made Clark such a dork, you almost didn't want him to be Superman. As the Real Life section shows, this is actually Truth in Television to an extent; most people aren't constantly looking for famous people around them.
Green Lantern: Clark hides behind a pair of glasses and you're worrying about me?
Flash: Clark slouches, wears clothes two sizes too big, and raises his voice an octave.
In the Superman/Batman storyarc "The Supergirl From Krypton", Kara is curious as to how the Clark Kent identity fools anyone as the pair of them stroll through Metropolis in civvies. About that time they come across the Superman statue in Centennial Park, Kara is awestruck by the reverence Earth holds her cousin in and realizes that most people don't see through Clark Kent because they see Superman as a godlike figure, and most of them wouldn't think to look for him standing right next to them.
Furthermore, it has also been suggested that the Kent disguise works in part because (in Post Crisis comics anyway) no one really knows Superman has a secret identity in the first place; after all, it's common knowledge that Superman is an alien named Kal-El who escaped his planet's destruction and lives in his Fortress of Solitude. But most importantly, Superman does not wear a mask like most other superheroes. This suggests to most people that he has nothing to hide. (As opposed to The Silver Age of Comic Books when everyone just seemed to know he had one.)
Superman also, while being very classically good-looking in his facial features and appearance, is fairly indistinctive. He doesn't have unusual eye or hair color, no facial scars of any kind, no identifying tattoos, or anything to distinguish him beyond just being an All-American looking guy. He has a certain degree of anonymity there. Clark's similarly nondescript appearance might make him a dead ringer for Superman but makes him similarly indistinct.
During The Silver Age of Comic Books, Superman would run into lookalikes often — from his Kandorian cousin to a movie actor — who were so similar to him that they could (and did) pass for him. This was an intentional plot point.
A Justice League comic written by Keith Giffen indicates, via a Spy Magazine "Separated At Birth?" feature (part of an authorized parody section), that society simply thinks the close resemblance between Clark Kent and Superman is an odd coincidence.note Justice League America #38 (1990)
Pre Crisis continuity too... besides the aforementioned shape-shifters, other popular means Superman used to protect his identity were the use of Superman (or Clark Kent) robots (in Silver Age stories; disposed of in the early Bronze Age) or Batman disguised as Clark/Superman.
A new element that has shown up recently is the fact that most people only know of Clark as a name in a byline, and only see Superman from a distance, if they see him at all. As most people don't spend a lot of time with both Clark Kent and Superman the similar appearance doesn't come up.
An early John Byrne Superman story had Lex Luthor hiring a computer expert to analyze data regarding the relationship between Superman and Kent (Luthor's theories included them possibly being close friends or even brothers). When the computer concluded that Clark Kent WAS Superman, Luthor immediately fired the analyst and berated her for being stupid. He could not accept that anyone could be so incredibly powerful and hide behind a human identity, let alone Clark Kent, instead of constantly and openly exploiting their might.
The reason Clark Kent's years as a television newscaster came to an end is that eventually the writers realized that showing Clark's face to the entire city on a nightly basis really should lead to someone figuring it out.
More of coming to an end due to the Byrne reboot, as he stayed on TV for 15 years (1971-1986). Though even while on TV, Clark used a few of the traditional tricks to cover his identity. One story (guest-starring the Atom) sees Clark "interview" Superman on TV by switching back-and-forth between identities at super-speed.
Subverted perfectly in the animated feature Superman Doomsday, in which Lois knows full well that Clark is Superman and is getting annoyed with the fact that he refuses to tell her.
It can get pretty infuriating at times when guys who should know better are fooled by the disguise. In Legends, Superman finds himself on Apokolips and Darkseid fails to recognize that he's Superman wearing glasses. It's ridiculous enough that a sharp-nosed reporter like Lois Lane is fooled by it, but you'd expect a telepathic god who's fought Superman many times would see through it.
Darkseid is probably either misled by the same logic as Luthor above (Darkseid would never pretend to be that weak, so neither would Superman), or isn't misled at all but is playing along for his own reasons... information that isn't obviously and immediately helpful right now can still be put aside for possible use at some later date.
Parodied when this particular demotivational poster, was altered to this
Prior to Superman and Lois Lane's wedding, after the two had been estranged for awhile, Superman is talking to Wonder Woman about when he first revealed his identity to Lois, and she had told him that she actually suspected it the whole time (the original issue just ends after he tells her he's Superman). In Batman: Hush, Batman also speculates that Perry White is too good of a reporter to not know who he is, but just never says anything.
The comics did do us the courtesy of lampshading it a lot. Once, after Superman came back from the dead (it's a long story), he and Lois were contemplating how to explain why Clark Kent disappeared. Superman, naturally, suggested several classic and idiotic Clark Kenting explanations. Lois told him no one would buy it. The explanation they did use? That Clark Kent was trapped under a fallen building for over a month and he kept up his strength by eating a nearby food cache and exercising.
And the funniest part of that conversation as Clark went through ideas from wandering the country with amnesia to alien abduction:
Lois: No offense, honey, but who would fall for such stupid stories?
Clark: Um, you did, Lois. All the time.
Saturday Night Live did a skit making fun of this. Clark's disguise was horrible! You could see his Superman suit sticking out at the collar and sleeves. Turns out everyone knew his secret identity and just played dumb. They decided to screw with him and tell him that Superman is gay. It's as funny as it sounds, especially since Superman was played by Superman fan The Rock.
Another sketch featured Conan O'Brien as "Moleculo: The Molecular Man". Everyone quickly figured out his alter-ego was Moleculo, because of his habit of looking into the camera whenever his name is said and saying "THE MOLECULAR MAN!!!"
By that logic, half the people here are Ciaphas Cain (wait for it...)
In probably the worst application of this trope, one episode of an old radio serial has Clark Kent accompanying Lois Lane to a Halloween party dressed...as Superman. When baddies attempt to do...something bad Clark Kent somehow manages to act as Superman and take them down, and STILL at the end of the day convinces Lois that he ISN'T Superman despite the fact he never changed out of his Superman costume or made any conscious effort to disguise his identity. (She comments on how similar they look at the end)
In the popular Elseworlds series Justice League: The Nail, Kal-El was found not by Jonathan and Martha Kent (whose car got a flat tire from running over a nail) but by an Amish family. After his adoptive parents were killed by the book's big villain, Kal took on the identity of Superman and joined the Justice League. In the sequel, "Another Nail", Kal is encouraged to take some time off. The Kents put together a disguise so he could blend in with the public. Their costume included a false beard and mustache that made him look rather creepy. Lois Lane then helped Kal with his disguise, suggesting a "less is more" approach; glasses, loose fitting clothes and a slight stoop to the shoulders. The disguise was essentially the classic Clark Kent look, prompting Kal to say, "You don't seriously think this is going to fool anyone?"
In one pre-Crisis story, Superman is to be featured on a postage stamp. He goes to great lengths to make sure that a side shot of him is chosen, rather than a full-face view, because if the stamp was postmarked in a town with a double-O in its name, the letters might land on his face in such a way that they resemble a pair of glasses, which might give away his secret identity. Presumably kids in the DC universe never doodle glasses and mustaches on newspaper photos, which might also be a bit of a clue.
Parodied in a MAD strip by Don Martin. Clark replaces his glasses with contact lenses, causing a receptionist at the Daily Planet to say, "Why, Clark! Without your glasses, you're, you're...why, you're SUPERMAN!"
In another Mad Magazine strip, Clark is depicted as having Superman's muscles nearly bursting out of his suit, and his cape sticking out of the back a little, commenting on what a Paper-Thin Disguise it was.
In a MAD strip, the Captain Ersatz Superduperman eventually reveals to "Lois Pain" that he's really "Clark Bent". She responds by walking over him and saying "Big deal. You're still a creep."
Except that those two pictures make Clark Kentingentirely believeable. Reeve really looks like two different people!
Superman: Secret Identity, an Elseworld story set in the real world where a man named after the fictional Clark Kent gets similar powers, takes great pains to avert this. When out saving people, Clark makes sure to never let anyone see his face. He wears the Superman costume to make the witness accounts all the more ridiculous and unbelievable. Halfway through the series, he does take to wearing fake glasses in his civilian identity, but only because he was temporarily captured and doesn't want whoever did it recognizing him while passing him on the street (and he gets a lot of jokes about it at work). He's not trying to prevent people who know him personally from recognizing him, he's trying to prevent people who saw him unconscious and imprisoned from recognizing him if he has the bad luck to bump into them on the street. When he does meet people face-to-face in costume, he uses makeup and forms to alter his features enough to be unrecognizable and burns his fingerprints off of anything he handles in front of them. Despite all this, Agent Malloy still figures out his real identity.
One comic had Lois hold Clark still so she could look at his face, obviously seeing some kind of resemblance, but just can't quite place it and gives up.
Smallville, though following the No Tights, No Flights rule of its producers until the Grand Finale, starts this in the appropriately named episode Identity, in which Jimmy Olsen accidentally caught Clark saving him and Lois on camera. Luckily, he is moving too fast to be seen clearly, but Chloe encourages him to adopt the identity of the superhero, "Red-Blue Blur". Lacking a distinctive uniform (except for the colours) and Reeve's skill in separating the personalities, Clark protects his identity simply by always moving so fast that he could only be seen as a blur.
In season nine, Clark wears a black trenchcoat with a white S as his costume, but still either stay in Super Speed or hide in the shadows.
Homecoming lampshades Clark Kenting by having Lois chastise younger Clark (not knowing that he's from the past) for showing up to work without his glasses, and later when Clark meets his future self and is taken aback by the glasses and slicked back hair.
As of Masquerade, Clark has finally officially adopted the Bespectacled Wimp disguise. The effectiveness is demonstrated when a guy runs into him by accident. He's profusely apologizing to the rather large young man who, earlier in the show, so blatantly oozed heroism that people were automatically respectful in his presence and almost fawning over him. And then he notices the new glasses and apology from Clark that it was probably his fault. Almost instantly the submissive demeanor essentially becomes "Out of my way, nerd!"
The Grand Finale has Clark in the classic Superman suit, which is also all CGI. Admittedly, Tom Welling may as well be the least convincing Superman actor when it comes to Clark Kenting. The flamboyant hair and limited change in demeanor doesn't help. It is probably best that we don't get to see Superman in the show much or the comparison would be absurd.
An episode of Lois and Clark has Lois attempting to get the paper sketch artist to draw a picture of Superman. Every time she describes a feature of Superman's face, like his broad chin, the sketch artist asks, "Like Clark's?", which Lois roundly dismisses, unable to conceive that Clark could look anything like Superman. Whether this helps or hurts one's suspension of disbelief is up to you.
An early episode resurrected the "lookalike" plot, where Lois and Clark briefly met an actor (also played by Dean Cain), who worked as a Superman impersonator, explaining why people might not immediately assume Clark was Superman simply because they looked alike
Lois and Clark really started to play with this trope as time went on. For instance, by Season 3 Lois and Clark were the Daily Planet's star reporting team, and were featured in it's advertisements, including posters with full-body photographs of them which were seen in the background several times. There were life-sized pictures of Clark Kent all over the city, and still no-one got it.
In an earlier episode, a man is fatally wounded in an explosion and dies in Superman's arms, his last words were "You know, you look kind of like Clark Kent, only without the glasses."
What really sold it was one episode where Lois, hiding out from a villain, adopts a disguise of heavy makeup, a red wig and large sunglasses, on the basis of "It works for Clark", the bad guy sees through it instantly.
In yet another example of Silver Age insanity, one comic sees Clark Kent get scouted to portray Superman in a movie. Everyone on set notices how Clark Kent and Superman look exactly alike yet suspect nothing. A full summary is available here.
Anime & Manga
Spoofed in Sekirei. Homura’s mouth cover would be moderately effective to hide his identity from people he only meets in the middle of battle once or twice, can’t really get a close look at him and have little or no chance to encounter him in his Kagari persona. He’s nevertheless absolutely baffled by the fact that Tsukiumi and Musubi, both of whom he lives with and have seen him very close-up in and out of disguise, can’t seem to figure it out.
Considering his power, the mask is probably necessary.
Subverted in Busou Renkin. During the attack to the school, Kazuki tries to disguise himself with a scarf covering his face but it doesn't work. Why? Turns out his friends have known him so long they can recognize him as Kazuki from afar just by the way he walks and don't even need to see his face.
In Harlem Beat, Shu of Three Men is the alter ego of Sakurai Shuuji. Their only differences are the shades and attitude.
Possibly played straight in the Pretty Sammy OVA series - this was one of the main reasons why Sasami didn't want to be Pretty Sammy (the other was that the costume is ridiculous). However, when she goes on her first fight, no one recognizes her, so she takes it as a good sign. However, there were only three OVAs made, so it's not known if they would have went the TV route.
Tokyo Mew Mew is a particularly odd case, considering that, in their Mew Mew forms, the Mew Mews only add a "Mew" to their first name (e.g. Mew Ichigo) and somehow that prevents people from figuring it out — granted, in the manga (the original Japanese version anyway), the names aren't written the same, but this doesn't matter when it's shouted across the street. Though, in both versions, Ichigo's crush Masaya nearly recognizes her in her transformed form, and later figures out her identity. Another exception is that Minto was able to recognize the mysterious Mew Mew as her idol/crush Zakuro.
Futari wa Pretty Cure subverts the trope because regardless of their hair changes in color and style the enemy quickly figure out who the Pretty Cure are. As early as episode 3 Pisard simply follows some girls he sees wearing the same school uniforms as the cures and picks them out in a crowd. From then on they are attacked personally whether in civilian form or not. This continues up through Heartcatch with the only people unaware of who the Pretty Cures are are their family and friends. The enemy knows who they are from the start.
And Smile Pretty Cure averts this big time - everyone who's snapped out of the Bad End spell easily recognizes the Cures. It doesn't help that Miyuki can't keep her big mouth shut.
The Pretty Cure All Stars movies also avert this through different means. The first movie have the girls figure out who was who after realizing they were going to places the others usually hung out at in their series. The second through fourth movies, their secrets are blown by their fairy companions, particularly DX 3 and New Stage, where Hummy's actions lead to them putting two and two together.
It was pointed out, though, in Yes! Pretty Cure 5, that their costumes did absolutely nothing to hide who they were, and panicked when they spotted the school reporter around. However, Natts usually steps in and uses his charm to woo her and get her to forget about capturing the girls on film.
Every disguise put on by Team Rocket for the main characters in Pokémon, ever. In fact, the only "disguise" the main characters didn't fall for was "invisible suits" consisting of black suits with veils over their faces, and those managed to fool James's parents (the joke is somewhat Lost in Translation, as said "invisible suits" are actually outfits worn by bunraku puppeteers, who by tradition are ignored by the audience as they perform). Except when they're using a disguise for something wholly nonthreatening, like Pokémon contests. During contests, Ash and Brock occasionally speculate that Jessilina is actually Jessie, then hand wave it (mostly because Jessie only ever has two useful Pokémon at a time and the heroes recognize them when used).
Spoofed in Mai-HiME. Akira tries Clark Kenting as the "Secret Ninja of the School", but is immediately recognized by Takumi and proceeds to deny her true identity.
In Detective Conan, after being shrunk to a grade-school kid, the title character does the same thing as Clark Kent: wears a pair of glasses to hide his identity. It ususally works well, until he slips up and says information he shouldn't have known unless he was really Shinichi Kudo, who was supposed to be a distant relative. This leads to his girlfriend, Ran, becoming suspicious of him several times, but she always ends up discrediting her own finds because the evidence doesn't quite match up, due to some outside interference (usually planned by the protagonist himself). In one scene, when the character Ai Haibara returns to her original age, Conan offers her his glasses as disguise, saying that they work well enough for Clark Kent. The response from Ai is, "So are you saying you're Superman now?"
Parodied in Dragon Half: A giant, winged demon tries to disguise himself by putting on a pair of glasses. Nobody is fooled for a moment.
Subverted in Dragon Ball Z. Not only does Gohan's future girlfriend/wife Videl figure out that he is the "Great Saiyaman" in about 2 minutes (slightly longer in the anime version), she also figures out that he's the son of the last winner of the "Strongest Under the Heavens" tourney before her dad. His classmates take a little longer, but only just.
Played straight with Master Roshi as Jackie Chun, though — he doesn't don his usual shades and put on a wig.
However, Yamcha figures that one out easily enough, though he can't convince anyone because Roshi superglued the wig to his head and called in a favor to have someone stand in the audiance dressed as him, and Goku, who is not noted for his ability to read people, figures out that Jackie Chun is related to Master Roshi.
Gintama's Katsura Katora does this frequently. He most often dresses up in a pirate costume and calls himself "Space Captain Katsura" (yes, he actually uses his real name), though he has also also used "Katsuo" on an occasion (as in, Mario from Super Mario Bros.) with his pet/companion Elizabeth taking on the role of Luigi. With the exception of the the three main characters, no one else ever recognizes him.
Exception: When he briefly disguises himself as Elizabeth in order to infiltrate Takasugi's ship and actually succeeds in hiding his true identity during the Benizakura Arc. Ironically enough, Elizabeth also briefly dresses up as Katsura during this Story Arc by putting on a wig.
In Moetan (a parody of magical girl anime featuring a protagonist who tutors students in English), the magical girl of the show almost blows her own cover. One of her first lessons to her classmate/crush is, in Japanese and English, "Don?t you think that magical girls look the same even after they transform?"
Exception: In Magical Girl Lyrical Nanoha, the only reason the characters aren't recognised on sight is the fact they tend to fight slightly out of phase with reality — on the one occasion a non-mage saw them, they proceeded to spend the remaining two episodes of the series raving about how nothing made any sense any more.
Ranma ½: Ranma was able to trick Ryōga into thinking that female Ranma was his sister, just by putting on fake fangs and a head band (and despite the fact that Ryōga has no sister). This was neither the first, nor the last time Ryōga fell for such a disguise.
However, it only works on Ryōga. Akane can still tell she's Ranma, though in the above case she was temporarily confused by Ryōga introducing "Yoiko" as his sister, not having realised how thick the Lost boy could be.
Subverted in Mahou Sensei Negima!! During the badge collection game, Yuna tries to trick Nodoka and Yue out of their badges, disguising herself with a mask during a festival. However, the two quickly realize who it is, as her distinctive side ponytail is quite clearly visible.
Later on, several people (Jack, Asuna, and Nodoka) disguise themselves in a busy place by putting on Clark Kent glasses... which are specifically labeled in author's notes as being a magical item with the effect of making the wearer blend into the background. Unfortunately, direct contact with other people tends to break the effect.
However only six girls in the entire series wear that style of belt buckle.
Subverted in Moldiver, when, once he has a hint of it, Professor Akagi only needs a few minutes to match the body shape of Hiroshi and the full-body-costumed Moldiver to confirm that they're the same person.
Puni Puni Poemi and Poemi Wantanabe look different enough for this to possibly work, except that they sound the same, have the same way of talking, both refer to themselves by the name of their voice actress, and the first time Poemi transforms into Puni Puni Poemi, she does it right in front of the Aasu sisters. Oh yeah, and they have the same name! And yet the Aasus are still surprised that Poemi is a Magical Girl.
Minami-Ke has Makoto dressing up as a girl so that he can keep visiting Haruka. His entire (very convincing) disguise consists of a hairclip and skirt.
After the successful hijacking of a plane with Yutaka Takenouchi headed towards the US, one of the hijackers tries to avoid arrest by going to Cromartie High School and disguising as Takenouchi himself. The hijacker's disguise is actually his own mask with the kanji for 'Take' in 'Takenouchi' imprinted on it, but it somehow fools everybody in Cromartie into thinking he is Takenouchi. His disguise is a setup for some crazy situations, one in which Masked Takenouchi tells a story that gives the impression that Takenouchi has changed his character for the better, as if he had a rough life and a big criminal record. (The imposter is in his 30's.)
Hayashida finally figures out at the beginning of Cromartie Volume 4 that there are TWO Takenouchis, as the real one has finally come back to the US... on a bullet train with Cromartie's students on it. It doesn't help at all, then, that Masked Takenouchi suffers from motion sickness as well.
Princess Tutu is another Magical Girl anime that uses this trope. Ahiru doesn't really look all that different from Princess Tutu at first glance—even her Idiot Hair is still there, although the rest of her hairstyle seems to be cut shorter. However, Fakir is actively looking for Tutu and never notices the resemblance until Ahiru behaves so suspiciously (while wearing the necklace that Fakir knows Tutu needs to transform) that Fakir CAN'T deny it anymore. However, the trope is justified similarly to Christopher Reeves' Superman—While Ahiru is klutzy, an awkward dancer and scatterbrained, Princess Tutu is graceful, poised, and expresses herself easily. Also, Tutu looks like an older version of Ahiru, including gaining a few inches of height and a more womanly figure.
This trope applies to Dark Magical Girl Princess Kraehe as well. The only difference between her and Rue is a different hairstyle, slightly narrower eyes, and heavy makeup, yet none of the characters seem to make the connection until Rue reveals herself.
Also to most people, Princess Tutu appears to be an enormous swan.
Not only doesn't anyone deduce any main character's secret identity in Sailor Moon (despite them using no disguise at all, with the exception of Tuxedo Mask and Sailor V), but most of the time the villains don't even bother to try. Notable exceptions are Nephrite and Zoisite: The former tried to find Sailor Moon by sending fake love letters from Tuxedo Mask, but eventually followed a false trail in the form of Naru; the latter discovered Tuxedo Mask's identity by pulling off his mask, proving that Clark Kenting seems to work on everyone but him. Most other adaptations don't seem to use the trope explicitly, although there they tend not to meet people they know while in costume anyway.
Usagi herself is the worst, surpassing even Superman. Her costume is identical to her school uniform, just cut a bit differently. She does not act differently in and out of suit (for want of a better way to refer to it, because again, it's a very very very minimal costume change.) Yet people who see both of them repeatedly never connect them, and yes, villains trying to find her identity did believe it was Naru (who looks, talks, and acts nothing like her) and not Usagi. Nothing less than directly witnessing her transforming can make someone connect the two.
The manga dodged this trope completely — many people do recognize the Senshi out of costume, most notably Mamoru when he meets Usagi again after having seen her as Sailor Moon, Haruka and Michiru, who deliberately keep their distance, and numerous villains that target the Senshi one by one outside of battle without ever having met them before. A few minor characters also recognized the girls if they knew them as civilians and then later saw them as Senshi. Yet oddly Zoicite even notices that Usagi has the same hair-style as Sailor Moon, yet shrugs it off as the current fad. Also, most of the later villains could sense the Senshi by their energy, rendering the whole secret identity thing pointless.
The manga scene referenced above has both Mamoru and Usagi recognizing each other as Tuxedo Mask and Sailor Moon while in civilian clothes — or at least noticing the similarity. The key difference is that Usagi denies the possibility of Mamoru being her Mysterious Protector, while Mamoru actually takes the fact into account, suggesting that the ability to recognize the characters in disguise really depends on the person. (In contrast to the anime version, where Mamoru seemingly fails to draw a parallel between the Moon Princess, Usagi and Sailor Moon almost until she actually transformed in front of him.)
And the best part? Even when they're transformed, they address each other by their civilian names. In front of everyone. Go figure.
This was possibly carried over from the original edition of the manga, where they do call each other by their real names, although with some of the manga villains being able to recognize them anyway, this was at least excusable.
This goes both ways, as many recurring villains are never recognised from one flimsy disguise to the next. In fact, most of the villains "diguises" are just a change of clothes and nothing else. Jadeite was probably one of the worst, frequently appearing in public without even so much as a mask or glasses. The English dub created an even more hilarious example - his name had been changed to "Jedite" and he was disguising himself as a priest named "Jed." Serena, who knows his name and his face, doesn't recognize him simply because he's changed his clothes.
Jadeite: This plan will surely work this time, because my glasses to disguise myself are much better than last episode's.
Also in the anime the Senshi themselves can't even see through each other's Clark Kenting without being clued in. They only recognized civilian!Minako because Artemis was with her despite meeting her as Venus in the previous episode. The first few appearances of Haruka and Michiru had them appear as shadows while in civilian form, then once their civilian form was introduced this stopped and it still took a number episodes for Moon and the Guardian Senshi to discover they were the same people (As well as the reverse) even thought it's blatantly clear to the viewers. Setsuna also has to tell Usagi who she is though she seemed to had guessed at it.
An interesting occurrence in the S season - Usagi and co. defeat Kaolinite and assume her to be dead. Some ten episodes later, Usagi visits Dr. Tomoe and sees Kaolinite there; and yes, she does go all "OMG the villain is alive!". But then Tomoe says it's just his assistant, Kaori, so Usagi assumes it's just two people with the exact same face and almost the same name. The dub (in which Kaolinite is called Kaori Night) takes it one step further - the "Kaori" alias was changed to... Kaori Night. So now, Serena assumes that they're just two people with the exact same face and the exact same name.
Usagi was also thrown off by the fact that Kaolinite was actually being nice and seemed normal. And she probably had to wonder why Kaolinite would be in a seemingly nice house and have stopped trying to extract pure hearts. But still, you'd think she'd keep a close eye on her (especially with Hotaru's behavior toward "Kaori") and have told the others about it.
The behavior difference is also likely what keeps Usagi and co. from recognizing Uranus and Neptune as Haruka and Michiru. When in their civilian forms, the two are very nice to them, in contrast to their Senshi identities. But, you'd think that the more experienced Haruka and Michiru could figure out that Usagi is Sailor Moon — unless you support the theory that no one in their sane mind would suspect a clumsy crybaby of being a "soldier of love and justice".
The Samurai Pizza Cats. People don't recognize them, even though they're fired out of a cannon built into the pizza parlor, they have the same names as their alter-egos, and their combat forms are largely their civilian forms with some extra armor and weapons bolted on. In one episode, the narrator remarks "No one recognizes our samurai heroes in their secret identities! Don't ask why, just one of the quirks of the show."
In Zeta Gundam, Char Aznable adopts the pseudonym "Quattro Bajeena", but his true identity is something of an open secret. The fact that he still uses a mobile suit in his signature color of bright red doesn't help.
This is more of a subversion - since most of the AEUG had never actually seen the infamous Red Comet, they wouldn't of known that this shade-wearing man was actually a Zeon Ace Pilot. It isn't until the heroes from Mobile Suit Gundam step in that Char's identity is revealed. It's later shown that the founder of the AEUG knew all along, and unsuccessfully attempted to get Char to reveal himself publicly and become the new leader.
In Gundam SEED Destiny, Athrun Zala pulls the same stunt Char did, disguising himself as "Alex Dino", Cagalli Yula Atha's bodyguard. People see through his disguise rather easily.
Kenshiro Kasumi in Fist of the Blue Sky disguises his true identity as "Yan-Wang" in public by giving himself a nerdy hairstyle and glasses.
One Piece: Usopp when disguised as Sogeking. The mask still reveals his long nose and he still wears his everyday clothes under his cape. The only two people fooled by this are Chopper and Luffy. Usopp eventually develops a split personality that talks and acts differently when wearing the mask.
In Urusei Yatsura, the Kunoichi character Kaede uses a pair of glasses to disguise herself. Everyone sees through it except the ninjas chasing after her, whose disguises are just as minimalistic. (One is wearing a surgical mask, the other just painted two stripes on her eyepatch, and the ancient clan leader is also wearing glasses.)
In Eyeshield 21, Sena is the eponymous Eyeshield 21, a running back with unbeatable speed. Sena is the only one with a build and height even remotely close to his "secret" identity. Most of the time he doesn't even bother coming up with a good excuse for not being there when Eyeshield 21 is. Mamori, his childhood friend and the team's manager, really takes a while to figure things out, given the clues she has on hand.
In Katekyo Hitman Reborn!, the title character often uses a variety of different disguises that can be easily seen through by the audience, but Tsuna is the only in-universe character that shares this view.
Subverted in Bamboo Blade. When Kojiro asks Tamaki to dress up as a new freshman named "Bureiba" in order to fulfill his kendo team's five-member quota, his old mentor (who coaches Machido High School's all-girls team) isn't fooled, and notices during a friendly match with Kojiro's team that Tamaki's and "Bureiba"'s fighting styles are similar. After challenging "Bureiba" to an impromptu match (and losing handily), he states that he knew all along, but lets it slide because it was just for practice
On the first glance, Lelouch from Code Geass doesn't clark-kent, the full face mask and all. But on the other hand, if you remember that Nunnally is blind and tells people apart by their voices... Yes he does.
There's a voice changer installed in his helmet. It doesn't make a lot of difference, but...
Lelouch also changes the demeanour considerably; as himself he's a soft-spoken, kindly big brother as far as Nunnally is concerned, while as Zero he is a megalomaniac Large Ham.
A straighter example would be Euphemia li Britannia, who disguises herself amidst hostages under a pair of Clark Kent glasses. Nobody, not even the perpetrators know it's her until she takes them off.
It helps that nobody knew that there would be Britannian princess present at all, so they weren't looking for her. Also, at this point Euphemia is not very important, as far as the Britannian royalty goes, and not that many people know how she looks.
Lelouch and Nunnally are also exiled Britannian royalty, and they hide in plain sight under their real first names but using the made-up last name Lamperouge. Granted, they were somewhat obscure, and only kids when they were exiled.
Subverted in Ryuusei no Rockman and Ryuusei no Rockman Tribe. Subaru Hoshikawa saves Luna Shirogane's life (several times!), but she does not know it is him. She has a crush on Rockman, and ironically, he is the same kid who goes to school with her and at whose house she tries to bake food for Rockman. Kizamaro Saishoin was one of the first to suspect that Subaru's real identity was Rockman, and by Ryuusei no Rockman Tribe, it's common knowledge to both him and Gonta Ushijima. Paradoxically, Luna refuses to admit this, and for the most part no one (even Subaru!) points out any of the many flaws in her logic. Eventually, however, as the series moves on, she seems to start like Subaru as well as Rockman, and in a touching moment before Rockman enters the Denpa-wave zone, she calls him 'Subaru' and tells him she is supporting him.
Subverted in Hayate the Combat Butler, when Hayate instantly sees through Nagi's disguise as "Mask the Money." But then played hilariously straight when Maria puts on sunglasses and claims to be a superhero maid — Nagi, her employer, fails to recognize her and wants to get her autograph.
Could be considered a Running Gag in the anime, whenever Maria tries to make herself incognito, she always chooses a pair of spectacles which has the effect of attracting gazes/confessions from guys AND being identified almost immediately from those she's trying to disguise from.
Subverted by Kamikaze Kaitou Jeanne in which several people comment that Maron and Jeanne resemble each other. In fact Miyako's whole reason for trying to capture Jeanne is so that she can prove Maron's innocence. Made even more ironic in that Jeanne has not only a different hairstyle but also a completely different hair color than Maron.
Used in an episode of Full Metal Panic? Fumoffu where Kaname disguises herself by putting her hair up and wearing a kimono. Nobody seems to think that that attractive blue haired lady looks just like the blue haired girl who left earlier.
In Dr Slump, Suppaman (an inept Superman parody) disguises himself as a reporter named Kuraaku Kenta. Naturally, Penguin Village being a Cloud Cuckoo Land, nobody ever recognizes him.
This does not fool Fuhrer Bradley for a second, with his Perfect Eye and all.
Zorro's usual costume plays this trope already quite straight, but in Kaiketsu Zorro, all Diego does is put on a cape, a hat and a less covering than usual mask that doesn't hide his friggin' hair!
If anything, Kotetsu T. Kaburagi (AKA Wild Tiger) of Tiger & Bunny is an even more over-the-top example of Clark Kenting than Superman, possibly in reference to him-his design has a lot of nods to Western superheroes, anyway. As it'd be cumbersome for him to wear his costume in public at company-sponsored parties, especially now that it's Powered Armor, Kotetsu has to act as his Wild Tiger superhero identity outside of his Powered Armor. It might have worked in his traditional costume, which looked a little like Batman's costume, as it made it harder to compare his alter ego's face to his actual face in the same way that Clark and Superman have the same face-but now that he's wearing Powered Armor, a skilled observer could easily tell that Wild Tiger and Kotetsu are one and the same. How obvious is the Clark Kenting, you ask? He goes about doing this by dressing exactly as he always does - same waistcoat, same Nice Hat, and same goatee - but with a Domino Mask. On public television.
At one point, Kotetsu tries to prove to an Apollon Media security guard that he's Wild Tiger after he's been Unpersoned by putting on his mask in front of him. The guard points out that most people (including him) don't really pay attention to what Wild Tiger actually looks like beyond a few easily replicated Distinguishing Marks, and that he could easily be a reasonably convincing cosplayer trying to sneak in — something the guard deals with all the time.
Somehow, it even manages to fool his own daughter.
Karina Lyle (Blue Rose) and Pao-lin (Dragon Kid) are also examples as they go unmasked all the time, using only colored wigs and, in Karina's case, makeup and colored contact lenses, to disguise their identities.
In Penguin Revolution, actor Ayaori Mashiba conceals his identity from the public by using the stage name "Makoto Ayaori," and by wearing Nerd Glasses and leaving his hair in a disordered mess when he's not on the job. The only person shown to ever see through this is the heroine, Yukari, who recognizes him only thanks to her unique ability to perceive star talent in the form of visible wings. The trope is justified in that Ayaori is an incredibly talented actor (although you'd think someone would at least notice the name).
THE iDOLM@STER - Haruka puts on glasses (and a hat) to avoid being recognized in public.
Subverted in the Magical Girl series Kaitou Saint Tail: while the only differences in look between Meimi and Saint Tail are the clothes and the ponytail, Meimi acts completely different as Saint Tail (most evident part, Meimi is quite shy but becomes a showoff as Saint Tail), takes great care at not using her magic tricks as Meimi (even before becoming Saint Tail, as she planned to become a professional illusionist and her father had told her to not show them in public until then) and goes to extreme lenghts to not show her face as Saint Tail. In spite of this, she was nearly found out a number of times, both by her rival in love Rina (a few stories were dedicated to Meimi's attempts at convincing Rina that Meimi wasn't Saint Tail, ending when Rina was traumatized into thinking that Saint Tail was a moustached adult man) and her Love Interest and Sympathetic Inspector Antagonist Asuka Jr. (who in the end concluded that Meimi and St. Tail are merely lookalikes).
Played straight and subverted in Samurai Flamenco. Masayoshi is initially the prime suspect when rumors about the title vigilante's identity begin forming, and he's only acquitted because an impostor steps in and claims to be the real Samumenco. Played straight with the Flamenco Girls, who are all popular Idol Singers in their civilian identities, and yet somehow effectively disguise themselves with little more than wigs and Domino Masks.
Identity Crisis. Deconstructed, as villains discovered the secret identities all the time. The answer: a little mind wiping by Zatanna.
In the Comic series Batman: Year One Batman pulls off Clark Kenting in his first attempt at doing vigilante work by using make-up to make a distinguishing fake scar on his face. People focus on the scar so much they don't notice any other real details.
Wonder Woman also uses glasses as a disguise, although she changed her hairstyle as well. The fact that her abilities are magic-based may also help.
The original version stated Wonder Woman co-opted the identity of an actual Diana Prince (who, miraculously, looked exactly like her). This Diana then took off for South America to get married.
She returned later to ask for her name and credentials back so she could get a job to support her family while her husband, Daniel White (no, not that Daniel White — although the physical resemblance is truly terrifying) worked on an invention. Wonder Woman took Diana White's place temporarily, and found Dan to be like most men in her comics, a pig who chained her to the stove. Once his invention was accepted by the government, however, Dan mellowed, since Mrs. White could now continue being Donna Reed.
Super Friends once did a segment on Wonder Woman's origin. She put on a tiny little eye-mask and yet no one knew her, despite both being a princess and the fact she's lived around the same people so much that they should be able to tell it's her.
Jay Garrick, the Golden Age Flash, was an odd case. In his early adventures, he didn't seem to put any effort into keeping his identity secret whatsoever, and routinely did stuff like trying out for the Olympics under his own name, running at super speed. And in any event, his "Mercury" style helmet left his face uncovered. Later stories did have him use his secret identity (and everybody else just forgot it, apparently). His secret was supposedly was maintained by subtly vibrating his face at super speed while in public. Then in 1978, the semi-retired Garrick went "back" to having a public identity.
Viciously parodied in the 1980s-vintage independent comic book Megaton Man, in which the title character is a grotesquely over-muscled hulk, whose attempts to hide behind a Kent-like blue suit and glasses fool no one but himself.
This is parodied constantly in The Tick, because the characters never appear outside their costumes. One episode featured him and American Maid posing as normal hotel guests, taking on assumed names, and the hotel concierge (working for the villain) only suspects something is up because the Tick picks an obviously made up name ("Nick Soapdish") and not because he's got two completely undisguised superheroes standing in front of him.
Subverted in Green Arrow, in one issue a cop that had been working with the hero turns up unexpectedly at Oliver Queen's home. Oliver asks in surprise "How did you know who I was?" The cop replied "Was it supposed to be a secret?" After that Oliver stopped even wearing a mask.
He was also instantly recognized by Mia Dearden, who pointed out that he uses a tiny little mask, has a one-in-a-million beard, and doesn't even bother to alter his voice when in costume.
In Arrow, this is avoided point-by-point: Because he does not adhere to Thou Shalt Not Kill, he has to hide his identity at any cost or never see the outside of a cell again. As such, he does alter his voice with a device that deepens it, doesn't have the comicverse's epic facial hair, and at least once has picked a method other than storming in in costume because he'd be easier to recognize during the day. There's still the matter of the mask, however: under that hood, he just uses a bit of face paint to cover the area just around his eyes; no more face covering than the comic version.
Played straight later on, when Oliver Queen was elected Mayor of his home city without anyone noticing the similar taste in goatees.
In a much older issue, Clark Freakin' Kent of all people tried to convince Ollie not to run for office, since being in the spotlight would make it much easier for people to realize he looked a hell of a lot like Green Arrow.
Captain Marvel Jr. is somehow able to keep a secret identity as Freddie Freeman despite the fact that his Marvel form looks exactly the same as his normal form. On the other hand, the fact that Freddie is legitimately disabled likely helps divert suspicion.
Likewise, Mary Marvel looks just like her alter ego Mary Batson, though Depending on the Writer, her superhero identity may be a "grown-up" version of her ordinary self. A bigger problem might be the fact that both identities share the same first namenote Albeit one of the most popular names in the English language, though this was avoided in the 1990s "Power of Shazam" series. In that version, "Captain Marvel" was treated (like, e.g., Green Lantern) more as a title than a unique name. Third parties would usually distinguish Mary from her brother by referring to her as "the lady Captain Marvel" or something similar.
Young Justice tried its hand at mitigating this—while the character never actually got to appear, there were plans for an appearance from "Lieutenant Marvel".
Golden Age superhero Captain Battle stretched the trope to the breaking point. In his civilian identity, he was William Battle, a World War I veteran who used to be a captain in the army. It didn't help that he didn't wear any disguise whatsoever while operating as a superhero. It doesn't help that he wears an eyepatch in both identities. One wonders how the intros for those stories went. "In his civilian guise, he is William Battle, the retired Captain! But when crime rears its ugly head, he puts on no disguise and becomes Captain Battle, man of mystery!"
Subverted in Invincible; best friend William figures out who Invincible is the first time Mark (Invincible) tries this in front of him.
It is however played straight with Atom Eve and Omni-Man. Especially when you realize that Omni-Man is both the world's most famous hero and, in his secret identity of Nolan Grayson, a popular and celebrated author.
Like the Superman example above Omni-Man/Nolan Grayson has fairly generic features to begin with. Furthermore as an author and writer (not a reporter) he can choose to keep a much lower profile than other celebrities and come off as a bit reclusive and eccentric. How many Calvin and Hobbes fans actually know what Bill Watterson looks like?
Subverted in The Authority. At one point, Apollo and Midnighter attempt to settle down in San Francisco, in order to give their daughter, Jenny Quantum, a vaguely normal childhood. As Apollo (a Superman Expy, who for this scene wears glasses) attempts to explain the concept of secret identities to Jenny, Midnighter ruins the whole charade by throwing the real estate agent 500 feet into a lake when he upped the asking price of the house they were looking at.
Parodied in an issue of The Avengers. Quasar, a member of the team, shows up at the mansion in his civilian identity and wearing a pair of glasses; every Avenger he meets thinks "I hope Quasar doesn't think those glasses are disguising anything."
Parodied in Gold Digger in the school days of one of the main characters. When some of the school staff turn out to be evil and try and conduct mind control experiments on the student body, Brittany "Cheetah" Digger's best friend convinces her to join her as a superhero as "Pink Avenger and the Cheets". Despite the fact that Brittany is the only werecheetah in the world, and the only non-human student in the school and probably city, the evil villains never saw through the disguise during their entire school stay. The rest of the student body, on the other hand... figured it out in about five seconds making it a big Everybody Knew Already to them, but keeping quiet out of approval.
Spider-Man is generally not an example due to his costume fully covering his body, but sometimes it still happens:
Perfectly demolished in a story in which Ben Urich places a call to Peter Parker's cell phone, implies that he knows Peter's secret, and requests a meeting. Once on the roof of the Daily Bugle, Spider-Man asks how Urich could have figured this out. Ben's response goes on for several panels. Some of the highlights: "Peter, I'm an award-winning investigative journalist at a major metropolitan newspaper. We've been working out of the same offices, and frequently assigned to the same stories, for something like eleven years now. I'm honestly insulted you thought I was never going to figure this out." "You frequently smelled like smoke. You know who else always smelled like smoke? Matt Murdock. You told me once that you knew Daredevil was Matt Murdock. Now, how could a substitute science teacher and part-time photojournalist possibly know that Matt Murdock, a blind lawyer in Hell's Kitchen, was the vigilante Daredevil. Oh, right."
This trope was further spoofed in another Spider-Man comic where Spider-Man briefly meets another hero, who is clearly a Marvel Comics parody of Superman. When this hero shows up without a mask on his face, Peter Parker asks how he disguises himself. The man's response is to pull out a pair of glasses and put them on. It fails.
Touched on in yet another issue where one of Spider-Man's contacts offhandedly refers to him as a New Yorker. When Peter responds with "How do you know I live in the city?" the man just smirks and replies "Ask me again with that Queens accent how I know where you're from."
In one issue of The Uncanny X-Men the beaten up father of Bobby Drake/Iceman, while lying in a hospital, asks Gambit a few questions. Bobby's father doesn't understand why some people engage in the X-Men although some of them are perfectly fine looking, just like Gambit, seeming to ignore his pretty unusual eyes. One can't blame him for that, even many colorists forget that Gambit doesn't have normal eyes, or make them blue instead of red.
Gambit's eyes are also hypnotic. It's possible that people just don't notice them.
Like everything else about Superman, this was parodied/deconstructed in Supreme Power. Mark Milton tells his government handlers he can disguise himself — and puts on a pair of glasses. The agents just shoot him that look. The fact that Hyperion has no secret identity and thus no real human contact is one of the reasons he becomes so unhinged later. Goddammit, they should've let him wear the glasses...
His original Squadron Supreme counterpart wore a tiny domino mask as Hyperion that covered no more than glasses would, and when the Squadron "went public", he removed it on television as if it were a dramatic Reveal.
Samaritan's civilian disguise in Astro City is just a pair of glasses and change of hair colour, but it's actually quite convincing, even to the reader. There is the fact that his civilian name is Asa Martin, an anagram of Samaritan.
In the early Silver AgeHuman Torch, "everybody knows that Sue Storm is the Invisible Girl, but no one knows her brother Johnny is the Human Torch". After the writers realized how stupid this plot point was, they retconned it into everyone knowing, but since they were aware of Johnny's attempts at hiding it, they respected that he didn't want them to talk about it. An earlier story where the brilliant Wizard tries, and fails, to learn Johnny's identity is quietly ignored, and he knows perfectly well who the Torch is in his next appearance.
Parodied in The Inferior Five, where even though only Awkwardman wears a mask, nobody knows their true identities. Even Awkwardman is pretty obvious. "Nobody suspects clumsy, oafish Leander Brent is really clumsy, oafish Awkwardman!... I wonder how come?"
More subtly parodied in The Intimates. The teacher of the Secret Identity class is Mr. Hyde (referring to the dual identities), who greatly resembles Superman and wears glasses. Lampshaded by one of the series' signature infoscrolls in the final issue after he finally uses one of his powers: "Can anyone guess what kind of 'vision' does Mr. Hyde have? (Hint: It's temperature based, as well as being the complete opposite of 'cold')"
Lampshaded in The Trouble with Girls. In one storyline, Lester Girls decides to try disguising himself using a pair of glasses and the pseudonym Leroy Gals. Though his internal dialog also mentions that he's also subtly altering his posture, voice, etc. He promptly meets and begins a romance with his reocuring foil who's disguised herself by wearing a brunette wig.
Conner Kent, the second Superboy, is one of the more ridiculous examples. He uses glasses like Clark Kent does, but he doesn't wear a freaking costume. His "costume" as Superboy is a black S-symbol t-shirt, jeans and work boots. That's right, he takes off his glasses and changes shirts, and no one recognizes him.
Cassie Sandsmark, the second Wonder Girl, wears a similar ensemble, but as of the most recent version of Teen Titans starting in 2003, she does not have a secret identity, which caused problems finding a school that would take her.
Though originally she had the ingenuity to wear a black wig and goggles, though even then her costume was mainly thrown together from what was already in her closet.
Power Girl carries on the Kryptonian tradition in her own series, simply wearing a slightly different hairstyle as Karen Starr. Although (especially as drawn by Amanda Conner) she is unusually good at dressing in layers, it's still hard to believe people don't make a connection. Indeed, several people do figure it out, which is lampshaded by Atlee, the latest Terra, who points out that Power Girl and Karen Starr look exactly the same. This was also lampshaded by Superman himself, who recommended against making Karen Starr the public face of her company, noting that she's not very good at maintaining an effective secret identity.note Power Girl #22 (2011)
Black Canary doesn't wear a mask, but the original Black Canary, Dinah Drake, wore a blonde wig, as did her daughter Dinah Laurel Lance, originally. The younger Canary now simply dyes her hair blonde, however, and while her secret identity was acknowledged to be a relatively thin one, it was made public by villains in a 2010 Birds of Prey storyline.
Red Arrow has one of the tiniest masks in comics. Seriously, it conceals about as much of his face as a pair of sunglasses would. Earlier in his career, as Arsenal, Roy Harper used sunglasses as his only mask. Even earlier, as Speedy, Roy wore a more traditional Robin-style domino mask.
Disney comics about superheroes both play it straight and justify it.
Super Goof (a 1960s parody of Superman) is Goofy in long underwear with a cape and his ridiculous hat with Superman's power set, yet no one could ever figure out why they never saw Goofy and Super Goof in the same place (his was carried over into animation through an episode of House of Mouse; at the end, Clarabell thought that Super Goof's secret identity was Dumbo). It's apparently because nobody WANTS to believe Goofy is Super Goof: the one time the Beagle Boys tried to use the police new supercomputer to find out his secret identity, everybody thought the supercomputer was still damaged by Super Goof's earlier sabotage when the computer actually told them it's Goofy.
Some stories have Mickey Mouse know Super Goof's secret identity, the implication being that either Mickey is that good as a detective or was just open-minded enough to consider and check.
In Italian Donald Duck comics, Donald has a superhero / Anti-Hero alter ego called Paperinik, who is Donald with a costume based on Fantomius with a domino mask and Donald's signature hat, yet nobody noticed in spite of people knowing their resemblance. It's explained due a combination of people not wanting to believe the lazy Donald is the city's idol and scariest person, Donald and Paperinik having appeared before people at the same time (due either robots taking Donald's place or volunteers replacing Paperinik), and Paperinik being a Master of Disguise who has disguised himself as Donald multiple times (or, in one memorable occasion, as a monster disguised as Paperinik diguised as John Rockerduck disguised as Paperinik).
The only people who saw through Paperinik's disguise and couldn't be fooled into thinking it was an error are Everett Ducklair, Lyla Lay and the Griffin, all from Paperinik New Adventures, and bypass Paperinik's usual tricks: Everett has Psychic Power and read it out of Paperinik's mind, while Lyla and the Griffin have technology that allows to see through Latex Perfection, and saw that Paperinik doesn't wear a Donald mask with a domino mask on it but only the domino mask (at which point it was easy).
In the first story it was even worse, as Paperinik only wore Fantomius' costume with his trademark hat and no kind of mask. It was actually a colouring error, as Paperinik was supposed to wear Fantomius whole costume (that includes a blue silk mask covering the whole face except the beak), but the colourist missed it and depicted Paperinik's face white (the novelization of the story Retcons it away as showing that Donald had considered wearing Fantomius' mask but in the end opted for the domino mask). Due the second story having Paperinik acting disguised as Fantomius (he had to infiltrate a costume party in Gladstone's place, with Gladstone planning to enter disguised as Fantomius), it wouldn't be until the third story that the domino mask debuted, by which time Paperinik was already The Dreaded.
Speaking of the third story... Most of Duckburg actually suspected Donald to be Paperinik, but after the police inspected Donald's car (that doubled as Paperinik's one) and failed to find Paperinik's devices (that had been removed beforehand in expectation of this inspection), the issue was dropped. The story ended with the first instance of Donald being seen in public at the same time as Paperinik (with Paperinik actually being a flying robot).
Daisy has her own superhero alter ego, Paperinika, who is a female and Straw Feminist counterpart to Paperinik. Despite this, the two don't actually like to work together and neither knows the other's secret identity. Which is fine... except that in the American translations, Paperinika is renamed "Super Daisy", but the stories are otherwise translated straight. This has the effect of making Donald look like a complete moron since he can't figure out who she really is, unless you've read Paperinika's original story: Donald's reaction to seeing Paperinika the first time was to ask Daisy why she was dressed that ridiculous way, and only got convinced it's not Daisy due to her acting much coldly and keeping a cool head in situations where Daisy would usually lose it (she was really pissed at the time. She later became an actress good enough to pull Paperinika's personality on purpose).
It's also implied that Donald is the reason Paperinika's disguise works: if Daisy's fiancee, who is known to be able to recognize identical triplets from near-invisible details, says she's not Paperinika and has a very vocal dislike for the latter, most people capable of recognizing Daisy through her costume will think it's just a casual resemblance.
Another example is when Paperoga (Fethry Duck) becoming the debatably useful superhero Bat-Paperoga (or "Red Bat" in other countries). It's an obvious spoof of Batman and it doesn't even try to hide the actual identity. It's Played for Laughs, and the identity is kept by a combination of the Red Bat's outfit giving actual cover and the Red Bat being seen as Crazy Awesome (in his first story he humiliated the Beagle Boys with the help of a headless gorilla) instead that the lucky Fake Ultimate Hero he is.
And taken even further with José Carioca's alter-ego Morcego Verde (Green Bat), another Batman spoof:note The main difference between the two being that Red Bat is a parody of Silver Age Batman (both in terms of costume as well as goofy gadgets) while Green Bat is a parody of the modern Batman (dark ominous costume and little to no gadgets) His costume is less concealing than Fethry's and while he's wearing it his friends still call him "Zé" or, at their most secretive, "Hey Zé... I mean, Morcego!" In this case there's no justification, only Rule of Funny.
The Beagle Boys once robbed a jewelry shop and avoided recognition by not wearing their masks despite being otherwise dressed in full Beagle Boy regalia.
Also played straight by Don Rosa in The Life and Times of Scrooge McDuck: when Scrooge first met them in his youth, the Beagle Boys (the original outfit composed by Granpa Beagle and his sons) were wanted criminals who couldn't show their faces in public, and started wearing the masks to hide their identities on suggestion of their employer Porker Hogg. It worked: they were even tricking the river police into leaving when Scrooge unmasked one of them, at which point the police recognized them and proceeded to arrest them.
While Vixen did wear a mask at the beginning of her career, her identity is definitely public knowledge by now. In Grant Morrison's Animal Man run, she showed up at the title hero's house in-costume, and Animal Man's wife was shown Fangirling over the fact that a popular supermodel was in her living room.
Spoofed in The Mighty Thor, when after losing the ability to turn into his mortal alter-ego Donald Blake, Thor has to come up with a new human disguise that will distract people from the fact that he's still almost seven feet tall with long blond hair and the physique of a god. Nick Fury hands him a pair of eyeglasses, noting that "they always worked for that other guy!" As if that wasn't enough, Thor then walks out the door and runs straight into a clumsy, oversized newspaper reporter named Clark, who thinks, "Gee, that looked like... I could have sworn... naaaah." It gets even more ridiculous when Thor grows a beard and maintains it in his civilian identity.
Later on, Thor's boss deduces that "Sigurd Jarlson" is far too athletic to be anything other than a superhero — clearly he is none other than Captain America.
Spoofed harder by Beta Ray Bill, who on one occasion reverted to his pre-Super Soldier form and toured New York City with an overcoat and a set of false glasses with rubber nose and mustache. The alien race Bill was born to, although roughly humanoid, are all hairless, lack external noses or ears, and are bright orange. The narration chalks this up to "New York being what it is".
Subverted with Eric Masterson when he wielded Mjolnir in Thor's stead, and actually grew a full blond beard whenever he transformed. It's even subverted by the Absorbing Man when he gets a good look at Masterson's face and realizes that Masterson isn't the same Thor that he's been fighting for so many years.
There was also the time Thor, in his later, more typical Clark Kent-ian alter ego Sigurd Jarlson, told a story to a friend's children about Thor and had to dodge accusations that he was really Thor himself afterwards. The children later discover the truth when they snoop in Jarlson's bag and find Mjolnir, although they promise to be good Secret Keepers and not tell anyone.
In various incarnations of the Teen Titans, Beast Boy puts Raven's attempt at a secret identity through its paces by frequently going to see her at school. None of her classmates seem to find it odd that she's constantly talking to green animals, though.
Kyle Rayner's first appearance as the new Green Lantern, before he chose the mask that covers most of his face, suggests that some people will be fooled and others won't. A woman rushes up to him proclaiming that he saved her years ago and asks if he remembers her, while a man comments on the new Green Lantern's different hair. Later stories suggested that no-one who knew him was fooled; the mask may have covered his face, but to anyone familiar with his artwork it was recognisably a Kyle Rayner design.
Supreme does it exactly the same way as Superman. As a kid he used to dye his hair, while changing into Kid Supreme, but he stopped when he realized nobody recognizes him anyway. At some point in a story Diana Dane realizes that Supreme and Ethan Crane look alike, but quickly dismisses it and points out some differences, like Ethan being shorter. She later suddenly realizes that Ethan IS Supreme. Supreme actually wonders why even Evil Genius Darius Dax gets fooled by it.
Greyshirt is a pastiche of The Spirit, and as such he doesn't have a dual identity... but news sources have widely speculated him to be former gangster Franklin Lafayette. Again, not that this matters because Franklin Lafayette is officially missing and presumed dead and Greyshirt doesn't keep a secret identity, but the point (and subversion) is that people are almost certain about who is under that mask.
For a brief time in Iron Man, Tony Stark decided to become a normal 9-5 worker and so he shaved off his facial hair and put on a pair of glasses.
There's also the Iron Man secret identity itself. The armor covers his whole body so it's not a straight example of this trope, but for years in the comic book Tony maintained the pretense that Iron Man was a separate person from Tony himself, a bodyguard with a secret identity. Having Tony and Iron Man appear together was easy enough thanks to stand-ins and robots, but such occasions were still so rare, and Tony was so rarely seen when Iron Man was busy being a superhero, that it's surprising so few people figured it out.
Somewhat mocked in Empowered, where while stalling for time, the titular heroine tells her captors that she's actually a guy and is wearing a highly convincing 'gynocamoflauge' suit to appear female, as nobody would suspect a hero's secret identity to be the opposite sex. When they buy it (because everyone knows superheroes are messed up), she goes on to claim that one of her male teammates is a woman in a male-looking armoured suit which she originally built to control her hot flashes, a female one is really a guy with very nice legs, and a third is actually a mutated cocker spaniel. Said teammates are not happy about this when the 'truth' hits the headlines.
Although Emp wears a mask as part of her standard costume (which is usually the only part of her costume to stay on, she had a job at one point as an Empowered impersonator, and put on a completely unconvincing Southern accent as part of her 'disguise'. Well, in addition to the knockoff Empowered costume.
Would you expect a superhero to work as an impersonator of herself? I wouldn't, and apparently the other superhero impersonators and a legitimate supervillain didn't too.
In Issue #0 of the Batwoman series Batman has been surveilling Katherine "Kate" Kane to determine if she is the person behind the Batwoman mask. He knows she has the skill to be Batwoman, she is the daughter of two career soldiers and she earned the position of Cadet Captain at the Military Academy at West Point, and she also has the motivation: her mother and twin sister were murdered when they and she were kidnapped in her childhood, but he does not know if she has the drive to be Batwoman. To test her he decides to "mug" her and see how she reacts, and he disguises himself with a black wig. Only a black wig. In the narration, he muses how "Clark" always said the simple disguises were the best. Batwoman herself averts the trope; not only does she wear a face-concealing mask, but her long red hair is actually a wig that covers her much shorter (albeit still red) hair.
Phantom Ladylampshaded this as early as 1942. She looks identical to Sandra Knight. Sometimes she had to go tremendious effort so people didn't see both of them. sometime her boyfriend and her father didn't notice it-which she always wondered why.
The Marvel Comics Avenger hero Echo utilized the perfect disguise to escape legions of ninja warriors. A man-suit. Being a slender female, bulky fake muscle/armor hid her curves well. Those without super-senses were fooled.
Fables has the Witching Cloak which can disguise the wearer in many ways and means. The Big Bad knows this and instructs his soldiers to question anyone with a funny backstory. A new soldier's transfer story is torn apart and he is slain. The wearer of the Witching Cloak had been a cleaning lady all along.
Played straight for a while in Wolverine, with Logan creating himself the secret identity of "Patch" in Southeast Asia, which consisted of putting on an Eyepatch of Power and not popping his claws. This was later subverted: apparently everyone realized there aren't a lot of short hairy men with wingtip hair, but decided it was safer to just humor The Berserker who stores knives up his wrists.
For a while, Starfire of the Teen Titans managed to keep a secret identity as a model by simply covering her glowing green eyes with a pair of sunglasses. Apparently no one noticed her orange skin. Apparently people just thought it was fake and a celebrity gimmick, but have you seen her body? Or her hair?
Perhaps the most over-the-top parody of this trope ever can be found in Elseworlds 80 Page Giant. It features a title page from a fictional Silver Age story where Batman's secret identity is Adam, as in "Garden of Eden" Adam. Despite the fact that he is the only man in the world, Eve still can't figure out that Batman and Adam are the same person.
In Irredeemable, flashbacks reveal that The Plutonian's secret identity was limited to Clark Kenting, plus changing his hair color and style (but not using a wig, apparently). Just like the trope namer, he worked in journalism, but seemed to do something more behind-the-scenes than actual reporting. And the fact that it's later revealed that the Plutonian is a Reality Warper neatly justifies any implausibility in the disguise.
In an interesting twist, when Nightwing took over as Batman following the latter's death, he had to work hard at convincing people that he was the original. The average citizen, unaware of the situation and obviously not too familiar with Batman, bought it instantly. Renee Montoya, on the other hand, saw through it instantly. Meanwhile, a story arc was made out of Two-Face figuring out it wasn't the same man he'd fought for so long and coming gunning for the new 'fake' to try and deduce who it was.
This happened earlier, back during the Knightfall storyline. Jean-Paul Valley had to work just a bit to convince everyone that Batman was back after his crushing defeat at the hands of Bane. Bane wasn't fooled for a second and dismissed him as a pretender. When JP armed himself with the armor, Harvey Bullock just mentioned that "the kid gloves came off". However, Commissioner Gordon just wasn't convinced that the Batman running around in armor was his Batman. Superman noticed it, too, but because he just recently came back from the dead, he really didn't have much time to investigate. The Joker noticed it, too, by his actions, as did Catwoman by his reactions around her. Though, with the exception of Superman, they didn't know that it wasn't Bruce Wayne under the mask, they knew it wasn't their Batman.
PS238 uses an interesting variation — Tyler is given a secret identity as part of his training as a Badass Normal. Metahumans, even those who go to school with him, can not recognise him once he changes into the costume. Only outright telling them to their face convinces them otherwise. Normal people who know him recognise him instantly and wonder why he's wearing a costume. Tyler wants to know how and why this works, because it doesn't make any sense.
In Big Bang Comics, Ultiman (the Captain Ersatz of Superman) doesn't wear a mask, and his identity as astronaut Chris Kelly is well known to the public. However, he keeps another identity — that of Carl Kelly, Ultiman's mustachioed black sheep twin brother. 'Carl' and 'Ultiman' are technically co-workers, as Carl is assistant to Ultiman's military superior Gen. Black. Those who know them both think Carl avoids Ultiman because he can't relate to or feels inferior to him, and because Carl's considered something of a bum nobody thinks anything of him leaving work in the middle of the day only to come back as if nothing happened.
Parodied in the Bizarrostrip for April 19th, 2013. Batman wears glasses in an attempt to hide his secret identity, but fails because he forgets to take off his Batman costume.
Subverted in the Tangled fanfic Super: a pair of glasses doesn't stop Rapunzel from immediately recognizing Eugene as the Gentleman Thief Flynn Rider she's been pursuing/flirting with in her superheroine guise as Blondie. Furthermore, Rapunzel is genuinely baffled by how Eugene doesn't seem to recognize her in turn because they've interacted with each other in costume frequently enough that he should be able to notice the similarities between her and Blondie even with her shorter brunette hair and meeker disposition out of costume. It turns out that Eugene did know who she was all along, but kept quiet about it because he had fallen in love with her and wanted to pursue a real relationship with her.
In the Dead or Alive fic Kunoichis Like Us, Kasumi disguises herself as an Ordinary High School Student named Sakura Misaka by wearing glasses and braiding her hair. Though Kasumi and the other DOA fighters are Famed in Story by the tournaments, the closest the public gets to any connection between Kasumi and Sakura is that Sakura looks like Kasumi. It's taken Up to Eleven when her school friends have "Sakura" cosplay as Kasumi and remain none the wiser.
Films — Live Action
In Man of Steel, Clark Kenting is deconstructed and reconstructed, Lois tracks Clark Kent through his aliases and good deeds, but he goes through a variety of looks in the movie, including a full beard, partial stubble, clean shaven with his hair slicked back and slouching with hats covering his face. Then when he joins the Daily Planet, his disguise is nothing but messy hair, a pair of very thick glasses (which he almost forgot to put on), lots of conflicting patterns and a tweed jacket and a less commanding voice. Lois obviously has no trouble recognizing him, but she plays along so the rest of the Daily Planet doesn't find out. Justified since she's spoken to Superman - slicked back hair and perfect posture in costume, (and Clark Kent, slouching but with a baseball cap covering his face and normal casual clothes, and a previous alias Joe, covered in snow gear and with facial stubble) personally several times while the others have yet to have seen him up close. Henry Cavill actually pulls off looking different, more or less (he's practically invisible as Joe the first time he and Lois meet), until the last version which may have been a shout out to Clark Kenting, in general.
Parodied in the Mike Mitchell adventure film Sky High with Mr. and Mrs. Stronghold, who both wear thick glasses. While Mr. Stronghold accessories with vaguely 50s-style clothing, Mrs. Stronghold just dresses like a normal mom.
Subverted in the classic Richard Donner Superman films, whose take on this trope has migrated to canon in at least some comic continuities. Christopher Reeve's vastly differing portrayals of Clark Kent and Superman really made you feel that he could get away with the disguise. To play the role of Clark Kent, he wore the glasses and slicked his hair back, sure, but he also slouched, stammered, and raised his voice by an octave so that there was a tangible difference between Christopher Reeve as Clark Kent and Christopher Reeve as Superman. This is most obvious in this scene from Superman where he's about to tell Lois the truth (but doesn't), and in Superman II where she figures it out on her own. All Reeve does is stand up straight and speak in his normal voice and suddenly he's another person. Superman II, 3, and 4 also throw in a form of Obfuscating Stupidity to the mix by making Clark The Klutz to add to the disguise.
In an interview given after Reeve's death, Margot Kidder (Lois) says that Reeve was adamant that Clark Kent behave nothing like Superman. To paraphrase Kidder, "Clark moves differently, his shoulders are held differently... he's a completely different person."
A similar good example comes in Superman Returns, where Lois explains Superman's height to Richard. Richard then says: "How tall would you say Clark is?" Clark draws their attention by clumsily knocking something over, then waves at them with a silly/embarrassed grin on his face, looking for all the world like a complete ditz, and Lois and Richard both burst out laughing.
Parodied in Mystery Men, as one of the character realizes that Captain Amazing looks identical to his "benefactor", but without glasses. (He disguises himself the exact same way Superman does.) The theory gets shouted down, as without glasses, he couldn't see anything.
Semi-Film, Semi-Real Life Example: Albert Walker of TheAgony Booth has twice admitted that he was fooled by the disguises of characters in some of the bad movies he's reviewed, which is shameful given the otherwise low quality of everything else in the given films. Specifically: Gene Simmons in Never Too Young To Die, who dresses up as a friendly agent despite his character being a flagrantly over-the-top transvestite, and Paul Freeman in Shanghai Surprise, supposedly dead and disguised, again, as an ally.
Count Olaf (played by Jim Carrey) in the film version of Lemony Snicket's A Series of Unfortunate Events disguises himself as a scientist named Stephano (false mustache and a shaved eyebrow) and a sea captain called Captain Sham (wooden leg, and a beard). Although in the books Olaf can easily be recognised when in disguise because he has a tattoo of an eye on his ankle, his disguises are still comically inept.
Lampshaded in the Bill Murray movie Quick Change where even the police were unable to give a good description of the robbers, as they were distracted by the unusual nature of the crime (A bank robbery by a clown.)
Lampshaded in the movie Rab Ne Bana Di Jodi: total nerd Suri disguises himself as fashion victim Raj by shaving his moustache, changing haircut and putting other clothes on. He later explains to a friend that if he managed to fool his wife with the disguise, it's only because God decided to help him. The trope is also slightly subverted because, like in Donner's Superman movies, it's not just the clothes that change but the character's whole behaviour. Suri and Raj talk, move and behave differently, which later leads Suri to become jealous of Raj because he wonders if people do not prefer him (why hello there, Split Personality!).
In The Adventures of Sherlock Holmes (1939), Sherlock Holmes (Basil Rathbone) disguises himself as a singer at a party. His disguise is so good that he feels audacious enough to get on stage in front of everyone and sing a tune. His disguise? Nothing more than a fake mustache. It's all in his facial contortions and mannerisms, and it comes across as plausible that nobody would recognize him.
In It Happened One Night, Peter and Ellie fool the detectives who are sent by Ellie's father with acting like a low-class married couple.
Subverted in The Phantom, or at least in the Rob MacGregor novelisation. Diana works out the Phantom's identity without much help, telling him that she first began to figure it out when he appeared moments after Kit disappeared.
Mocked by MAD in their spoof of the Teenage Mutant Ninja Turtles movie. April: "Why do you wear a mask?" Raphael: "So no-one knows I'm a turtle, of course!" The turtles' masks are doubly silly because they don't have a secret civilian identity: if anything, their masks exist to reveal their identity, not to conceal it.
Cillian Murphy's character in Peacock is a quiet wage-slave who keeps to himself. Cillian Murphy's other character in Peacock is a woman who lives in the same house, looks curiously similar, and often appears right after Cillian has gone upstairs (you know, plus the time it would take to put a wig and some eyeliner on). Nobody ever gives any sign of knowing, the only possible rationalization being that maybe in small-town 1950s Nebraska, maybe it just didn't occur to them that Cillian Murphy would probably wear a dress given half a chance.
In Sugar & Spice, the cheerleading squad robs the supermarket bank branch, dressed as...cheerleaders. In Betty doll masks. Arguably Fridge Brilliance as: 1)Who would suspect actual cheerleaders of robbing banks, and: 2)The number of cheerleading groups in a general area.
Subverted hilariously in Green Lantern. Hal Jordan tries to disguise his voice while speaking to Carol Ferris. It works for about a minute, but as soon as she gets a good look at him she knows who he is.
Carol: I've known you my whole life! I've seen you NAKED! You don't think I would recognize you because I can't see your cheekbones?!
Jason puts on a fake mustache to imitate his father to fool the principal in Mystery Team. It doesn't work.
Played with in Steel where the armor covers almost all the protagonist's body. Unfortunately, the title character is 7 feet tall, so it's completely obvious to anyone who sees him in both identities. Lampshaded by the Big Bad:
Played with in The Prestige. Borden (Christian Bale) and Angier (Hugh Jackman) often adopt disguises to sneak into each other shows, but they tend to just be false beards that don't fool anyone who knows them. Then at the end of the movie, it turns out Borden's identical twin (also played by Christian Bale) had been disguising himself as the assistant Fallon the whole movie, and concealed it by wearing big glasses, a hat, a false beard, not speaking, and makeup to make his face look chubbier.
The Rebel Set, a 1950s B-movie crime caper, had ringleader Ed Platt disguising himself to evade detection from his own gang by wearing a clergyman's collar - this was called out mercilessly on MST3K.
The villains in A Series of Unfortunate Events seem to be quite good at this, possibly because most of them are identified by a few distinguishing features — such as a monobrow, baldness, or very pale faces.
Cleverly averted in The ShadowPulp Magazine, where readers are first led to believe his secret identity is Lamont Cranston (as he is in the radio show) but the very next novel has the real Lamont Cranston wake up to The Shadow, Master of Disguise, in his room, quite perfectly borrowing his face. The Shadow also commonly goes by five other identities, some borrowed, some invented, as well as single-use identities in many stories. Readers had to wait seven years to find out his real backstory in "The Shadow Unmasks," which involved Faking the Dead twelve years beforehand and arranging to be miraculously "found" when he needed a new primary identity.
Ripliad: Tom Ripley pulls this off very successfully in the first novel: blonde hair and a big smile, and he's Dickie Greenleaf. Slightly darker hair, a meek slouch and non-prescription horn-rimmed glasses, and he's Tom Ripley. Subverted twice because (a) the novel goes into extreme detail about Tom's preparations and his fear of being caught, and (b) Tom is so completely batshit insane, he almost believes he's two different people.
In Stieg Larsson's Millennium series, Lisbeth Salander had insisted on her punk rocker girl appearance so heavily, even comically exaggerated it during her trial, that she could adopt any other persona and nobody would recognize her, as they were not expecting that. She disguised as a blonde and carried a fake passport by the name 'Irene Nesser' and nobody, policeman, border guard or airport security man cared to look closer.
In David Eddings' The Malloreon, 'Zakath takes advantage of this after he's more or less shanghaied into joining the companions on their quest. Despite being the Emperor of nearly half the world, all he has to do is grow a beard and change clothes to go unrecognized; he explains that most of his subjects have only ever "seen" the Emperor as an image on coins, and of the minority that have seen him in person, most saw only the guards, attendants, and trappings around him. No-one would expect to see the Emperor riding through the backcountry unattended, unshaven and in ordinary clothes.
Hallis Saper, for the first half of Starfighters of Adumar, wears a pair of eye-concealing goggles over her eyes and a 3PO droid head ("Whitecap", which houses her recording equipment) on her shoulder. This outfit turns out to have been created for just this purpose: when she wants to be more circumspect, she simply removes the goggles and tucks Whitecap under her cloak. After Whitecap malfunctions, she's forced to abandon this outfit, to the point that it becomes a minor Running Gag that people don't recognize her (since, after all, they're expecting the two-headed lady).
This phenomenon is mentioned in a few Discworld books, but Moist Von Lipwig of Going Postal and Making Money turns Clark Kenting into a lifestyle and an artform. He has very in-distinctive looks normally, so he adds accessories like beards and moustaches, a spot of makeup, a Verbal Tic in order to give any eyewitness report something to latch on. In his official duties, he wears very distinctive clothing to distract from his face, and when the newly formed newspaper reporters come to interview him, he fights tooth and nail to avoid being clearly photographed.
In Beyond The Blue Moon, Rupert and Julia return to the Forest Kingdom as Hawk and Fisher, and count on their both having aged to conceal their real identities. With the masses, it seems to work, mostly because their official portraits are so idealized as to look nothing like they'd looked even when they were younger; at the end it's subverted, as everyone who'd actually known them admits that they'd recognized them both immediately, but kept quiet about it for reasons of politics and/or to respect their wish for anonymity.
In the earliest version of Beauty and the Beast, Beauty is visited in her dreams by a prince who begs her to save him and she fails to realize that he and the Beast are one and the same until his transformation. This normally wouldn't qualify as an example of this trope due to the handsome prince and the hideous Beast looking nothing like each other, except that the prince wants Beauty to realize his real-life identity and does everything short of telling her outright, including telling her that she's made him unhappy right after she refuses to marry the Beast and changing places repeatedly with an image of the Beast when she asks how she can help him. Which makes Beauty look like an even bigger dumbass than Lois Lane; at least Superman actively sought to throw Lois off his scent, whereas the prince CONSTANTLY tells Beauty to look past appearances and find him "no matter how I may be disguised"!
LazyTown villain Robbie Rotten wears at least one Paper-Thin Disguise in all but a few episodes, yet is never recognised even by the adult characters until he is 'unmasked', usually due to his hat falling off. In one episode, he removes all but the headpiece of his costume, yet is not recognised until the headpiece comes off, and in another episode (The Laziest Town) serves free ice cream to the townschildren unquestioned while wearing just a false moustache and a food service hat.
Subverted later in the same episode, when Robbie walks into Mayor Meanswell's office still wearing the moustache. The Mayor had this to say:
Mayor: Hi Mr. Rotten. Did you grow a moustache?
Teri Hatcher, appearing on Saturday Night Live during the run of Lois and Clark, got the opportunity to mock this during her opening monologue. She starts by telling the audience about the teasing she gets for playing the clueless Lois Lane, but explains that it's just part of the show and nobody is really that dumb. Then Will Ferrell comes on and asks if he can make an announcement. He puts on a pair of reading glasses... and Teri starts panicking, asking "Oh my God, who are you?! Where's Will?!"
While Cain isn't quite the master of dual roles that Reeve was, he still did a fairly good job of making Clark and Superman two very different characters. Clark is cheeky, casual, and aggressive when he has to be. Superman is stiff and authoritative.
In terms of the secret identity even being an issue, Lex Luthor's realization that Superman has a secret identity and "walks among us" is a key turning point for Luthor's antagonism toward Superman partway through Lois and Clark's first season.
In another episode, Lois gets Supes' powers and dons a costume as "Ultrawoman". Just before facing Jimmy and the Chief, she panics: "They'll recognize me." "No they won't," Clark calmly assures her — and they don't!
In another famous scene in Lois and Clark, Tempus, a man from the future, comes back in time and tells Lois that she's famous... for being "the most galactically stupid woman who ever lived", demonstrating by putting on and taking off a pair of glasses over and over saying "I'm Clark Kent! No, I'm Superman!" Turn that light down, would you?
The assassin Deathstroke (no, not ''that'' one; this guy had magnetic powers) donned a pair of glasses when he and his wife socialized with Lois & Clark in their civilian identities and neither he nor Superman recognized each-other, despite having given the Man of Steel a serious beating earlier, which proves even Superman can be fooled by a pair of specs.
A few people have noticed how much Superman looks like Clark Kent without glasses. They're either dying in Superman's arms or, in the case of Lois, waved it off as being under the influence of a Love Potion and idealizing the object of her affection (Clark) as looking like Superman.
At one point, when Clark is about to be outed as Superman, Jimmy Olsen comments "I always thought that Clark looked a lot like Superman, but I never thought he was Superman." To which Perry White replies "I've been told I look a lot like Elvis, but I've never been to the White House."
With the love potion, Superman pretended to be influenced by it when he had had it applied to him in his disguise, so Lois did have a situation where Superman and Clark seemed to react to the potion differently, making potion reaction a theoretical difference. Why this does not cause an unrelenting investigative reporter like Lois Lane to want to know why Clark can resist something that overcomes even superman probably raises more questions than it answers.
The in story explanation was not that Clark was immune to the potion, but that he wasn't attracted to Lois enough for it to have an effect on him (since it only enhances existing feelings).
Jack Styles from Jack of All Trades wears a hat and mask to obscure his identity as the Daring Dragoon, but doesn't do anything to hide the fact that he's the only one on the island with an American accent, that he has the same style of ridicule toward the captain, and showed up the same day Jack did.
Hilariously referenced in the live-action Tick series, where a Superman-like hero dons a pair of glasses (still wearing his costume), and The Tick immediately mistakes him for someone else.
At the end of the episode, the hero was taking off and putting on his glasses every few seconds right in front of everyone, and The Tick forgot who he was each and every time.
Regularly parodied in 'Allo 'Allo! with LeClerc. Whenever he arrives in one of his pathetic disguises, he pulls Rene aside and says "It is I- LeClerc!". He confirms this by raising his glasses, which is a bit absurd since he normally wears glasses anyway. On occasion, he has revealed himself by removing a false moustache... exposing the nearly identical real mustache he always has. Naturally this exasperates Rene no end.
The Power Rangers. You'd think with face-concealing helmets they'd have it made, but their idea of keeping their identities secret is to always hang out together and wear clothes that, in some way, correspond to which Ranger color they are. The original Rangers seemed to own nothing that wasn't their Ranger color (to some actors leaving the series with an "I don't wanna see anything pink again as long as I live!" attitude toward their colors.)
Somewhat justified by the full face helmets and the fact that the color clothes are a subtle clue.
There are also some episodes wherein people try to find out the Rangers' secret identities, but once the truth glares them in the face they ignore it. Then what was the point of trying!?
Many is the time the team members call one another by name in front of civilians with nary a consequence. Hilariously subverted in Power Rangers RPM, where the "Ranger (Color)" designation is often used in combat when they are one of the teams whose identities are NOT secret.
It gets worse in VR Troopers. They don't have designations, and the suits don't have a dominating color; until Ryan gets his upgrade, which is blue, they'd all equally qualify for "the red one." Their official morphed designations are VR [Real Name Here] according to The Merch. Nobody ever figures out who they are.
Wild Force is one several seasons where the Rangers simply don't have secret identities, or simply don't bother to maintain them (others being Lost Galaxy, Lightspeed Rescue, Time Force, SPD, Operation Overdrive, and RPM). They seem to dish out the information on a need-to-know basis, but don't actively try to keep the secret.
In Power Rangers Dino Thunder villainess Elsa manages to spend most of the season working as the principal of the Rangers' high school. Her disguise is limited to a business suit, glasses, and eventually, a haircut. It's even lampshaded practically by name when her identity is revealed.
This one is especially bizarre as with the way the reveal is played, it seems the producers seriously thought the audience wouldn't recognize her either.
Hannah Montana. All the girl does is put on a wig and sparkly clothing and she is instantly unrecognizable.
Miley Stewart does tend to act a bit more "small town country girl" when she isn't Hannah. Maybe not Christopher Reeve level, but still a possible example of personality making a difference.
Her best friend and sidekick disguises herself by wearing multi-colored wigs and dressing up in punk(ish) clothes. Her father disguises himself by wearing a fake mustache. When Miley's male friend was let on the secret, he adopted his own on-stage disguise, wearing a fake goatee and dressing in sports/stereotypical rap clothes. And amazingly enough, no one is the wiser.
Her father's disguise is the weakest of all of them. He doesn't even wear the mustache all the time. Does he even care if anyone figures out that Hannah and Miley are the same person?
The show did lampshade this in one episode where Jackson calls out the Trope Namer himself while Miley and Robbie are getting in costume.
Played straight in Battlestar Galactica with Gina, the Number Six Cylon who assassinates Admiral Cain and later hides out on Cloud Nine, hidden only by a wardrobe change and glasses. RDM admitted in the podcast that it wasn't one of their best moments.
There are no critical plot points hinging on Gina not being recognized by someone who already knows a Six well.
There is also The Plan where two Sixes, Shelly Godfrey and "Tough Six" appear side by side, yet don't seem to be noticed. Somewhat justified in that they do look and act different. Godfrey wears a suit, glasses, has blonde, fluffy hair and an insecure demeanor. Tough Six was wearing leather, chains, had brown, straight hair with blonde streaks and acted far more aggressively. Cavil lampshades it, noting the effort Sixes take to differentiate themselves. Also, this was before it became public knowledge that humanoid Cylons (a) existed and (b) had copies. A human observer would think they were normal twins.
Far more noticeable was the Doral copy, after another Doral had been on the ship as public relations officer. He thought it would be enough that his suit was teal and the other's had been burgundy. This is why Cavil had him blow himself up.
Colin (as Superman/Clark): Now they recognize me... (mimes taking off glasses) Now they don't... (removes glasses) And now they recognize me...
In Unhappily Ever After, Tiffany tests the theory that guys only like dumb girls by chatting up the same guy in the school library as though she were two different people, one smart and one stupid. The only visual difference between her two personae is a pair of glasses; she doesn't change her clothing or even her hair. It still fools the guy.
The Cape at least has a mask, but somehow no one recognizes him from seeing the lower half of his face and hearing his voice. This includes his archenemy, his old partner, and his wife and son.
Slightly justified in that he's supposed to be dead, and no one expects a dead guy to be a masked hero.
Dark Justice: Judge Marshall goes unrecognized when he lets his hair down and takes off his glasses, allowing him to become a Vigilante.
Humorously referenced by the Initiative guys in season four of Buffy the Vampire Slayer, though their full body and face mask suits are far more convincing than Superman's disguise.
Forest: This is the burden we bear, brother. We have a gig that would inevitably cause any girl living to think we are cool upon cool, yet we must Clark Kent our way through the dating scene, never to use our unfair advantage. Thank God we're pretty.
Nobody at Amanogawa High School ever seems to connect Kamen Rider Fourze to Gentaro Kisaragi. This might not look like an example since Kamen Riders wear full-body costumes and helmets, but Fourze and Gentaro are both boisterous goofballs and Gentaro's friends can be seen at every one of Fourze's battles giving him advice (and calling him by name). And it's not a visibility issue, since Gentaro is actively trying to befriend every single person at AmaGaku and is therefore known all over the place. It might help that civilians rarely hang around Fourze's battles and he doesn't get any press. He doesn't even try to hide his identity, so it may not be an issue (the Power Rangers and Super Sentai teams who don't hide their identities don't seem to get mobbed in the streets for autographs and such either.)
The same series has Kamen Rider Meteor, who even Gentaro and friends don't recognize as their friend Ryusei Sakuta. In this case, Ryusei does have to hide his identity, as a condition of being able to continue being Meteor. He actually does try to act completely different, being quiet, friendly and cowardly normally while being brash, arrogant, and a competent fighter as Meteor. Interestingly, in his debut episode, Gentaro sees right through the Clark Kent act, saying that he won't befriend someone who's lying about who he is. Later in the episode when a frustrated Ryusei punches Gentaro in the face, Gentaro says that they're cool now because he got a glimpse of the real Ryusei in that punch.
As of #27, Meteor's identity has been exposed and found out by Cancer Zodiarts. What's bad about it is this is all Ryuusei's fault.
What's worst is the name. Ryusei is a word for meteor. Nobody ever says "hey, how come Mr. Meteor always leaves and five seconds later Kamen Rider Meteor shows up?" Ever.
Wonder Woman TV series: While this trope was played straight in all the series, it was notably averted at "Mind Stealers from Outer Space (Part 1)" when the Skrills, an alien race who steals minds to sell them into slavery, discovers easily Diana Prince's secret with only a slide projector:
Unquestionably, the same human.
Subverted, amazingly, in the Disney Zorro series. Despite Diego wearing a full costume and mask and pretending to be an unathletic coward in his own persona, Capitan Monestario still deduces his identity from noticing that Diego was always in the same vicinity whenever Zorro appears but the two were never seen together. Diego's servant Bernardo has to crash Diego's trial dressed as Zorro to ruin Monestario's plan to expose him.
Many, many incarnations of Diego have their bacon saved by Bernardo putting on a Zorro outfit.
Also during the episode, it's shown that many people in the Pueblo can look like Zorro while wearing his costume, even one of Monestario's own men.
An interesting example in the BBC Series Good Cop. John-Paul realises that Someone saw him walk out of the house where he murdered a criminal, when the witness is placed in a cell (For a different reason) John-Paul asks him if he saw a man last night and keeps telling the witness "Keep looking at me." so the witness in question doesn't think that he really saw John-Paul at all and that he's just gotten his face stuck in his head.
1970s Saturday morning series Electra Woman and Dyna Girl. These female versions of Batman and Robin wore no masks, but merely wore their hair differently as super heroes.
Practically inverted in Merlin. Merlin's Older Alter Ego looks, sounds, and acts nothing like him and yet everyone says his "eyes are familiar". And it's not like he has an unusual eye color or anything, they're standard blue eyes in a cast of blue eyes that everyone picks up on. Even when he disguised himself as an old woman (very convincingly at that), Arthur kept wondering if he'd met "her" before. Although, given that Arthur is extremely Wrong Genre Savvy, whatever guess he had had to be miles off.
Series/MANTIS is one of the best examples. Nobody would expect the mild-mannered, paraplegic scientist Dr. Miles Hawkins of being the superhero called M.A.N.T.I.S. Also an example of Clothes Make the Superman—he can't walk without the supersuit (though he's trying).
Doctor Who: In "The Daemons," the Master dons a pair of Clark Kent-like glasses as Rev. Magister.
Done for laughs on the third-rate variety show ("Second-rate variety show!") The Muppet Show by Mark Hamill. He first appears in full Skywalker costume, and gets pegged as Hamill right off the bat — only to run out the door to get his "cousin" and reappear seconds later dressed casually as Mark Hamill. At the end of the episode, both appear onscreen just to mess with Kermit's mind.
This is Older Than Steam: in William Shakespeare's play King Lear, the Earl of Kent(!) returns from banishment in a fairly flimsy disguise to help the king. Even before he goes mad, Lear fails to recognize him along with everyone else, despite having known him for years.
Later in the play, after Edgar is accused of plotting against his father the Earl of Gloucester, he tears at his clothes and covers himself with mud to disguise himself as a "Bedlam beggar". The disguise is good enough to fool his father, his godfather King Lear, the Earl of Kent (who is also in disguise and who Edgar fails to recognize) and the King's fool (easily the smartest person in the whole cast). In the final scene of the play, Edgar dons another disguise that fools his half-brother Edmund, though the stage directions imply that he may be masked.
In fact, many of Shakespeare's plays use this, including most of the comedies. In Measure for Measure, the Duke, who rules the city, wanders around speaking to all the main characters with no attempt at disguise other than a priest's robe. In Twelfth Night and As You Like It women dress as men with little effort other than wearing men's clothing. Rosalind (the protagonist of As You Like It) remarks, in short, that no one will pay attention so long as she wears breeches and carries a sword. Orlando, the man in love with her, doesn't recognize her, even when she "pretends" to be Rosalind so he can practice courting. Most scholars agree these disguises would have been useless and flimsy, so the audience could easily see through them. This, mostly, is the joke, because women were not allowed to act in Shakespearian times; you would have a man who was playing a woman who pretended to be a man imitating a woman and so on. Also, until roughly the 1950s, clothing was how you told who was a man and who was a woman. People just went with the gender suggested by the clothing.
Pick a Mozart opera, any Mozart opera — and many, many others.
The Barber of Seville (both the original play by Beaumarchais and the opera by Rossini) play this for laughs.
This brings up some confusing Fridge Logic. Do the agents believe you're what you say you are? Do they think you're a fellow agent disguising yourself? Or do they see through the disguise, but can't call you on it without also compromising their own disguise, which they hold onto for fear of being found out by their fellow agents who they don't realize are fellow agents and oh dear, I've gone cross-eyed.
The item makes the disguise in a sense. Through use of the Clairvoyance ability you can actually see how the agents perceive you. With no item in hand they see you as a cardboard cut-out of yourself looking shifty and sly. Item in hand, they see you as whatever you present yourself as, again as a cut-out. Paper-Thin Disguise indeed.
You can also (in the real world) slip by the very nearsighted Crispin by wearing a straitjacket, an award statue that looks like a claw-hand, and a framed portrait of his boss.
Played with in Super Robot Wars Original Generation 2, where Elzam's disguise as Rätsel Feinschmecker is utterly transparent, and he knows it. But because it gives the rest of the group Plausible Deniability about the fact that an ex-Dragon is working with them, everybody goes along with it. This mostly consists of substituting "Rätsel" for "Elzam", even when talking about something that was officially done by Elzam.
He even gets away with just ditching the disguise when he has to go to a funeral. It would be tacky to wear the disguise to the funeral, after all.
A minor one in the original Valkyrie Profile: This happens during a chance encounter with the princess Jelanda and the mercenary Arngrim (the first two party members Lenneth picks up); Jelanda is able to hide her prim and girlish appearance with thick glasses and a babushka; both effectively make her look like an older woman.
Metal Gear Solid 3: Snake Eater has the spy EVA very obviously disguised as a scientist named Tatyana. The only difference is adding a pair of glasses and making her hair a little neater. The game treats this like some amazing secret, with Snake & Co. repeatedly wondering who on earth that girl could be, and dropping little hints.
Mocked in Peachi's comic version, where Ocelot actually figures it out and repeatedly tries to tell his commander, only to get rejected out of hand every time.
Snake does this no less than twice. First, he must pose as a scientist to infiltrate a small weapons lab. He puts on a lab coat and glasses, and doesn't even bother taking off his bandana. The second time, he must pose as a maintenance worker to infiltrate an even larger fortress. Only now, he also has an eye patch, and the enemy knows his face.
Humorously, wearing the mask you get at the start of the game makes it easier for the enemy to see through both disguises.
Also subverted with the real scientists in the first instance to an extent. They see through Snake's disguise easily, but only if they see his face.
In the video intro to Rayman Raving Rabbids 2, Rayman infiltrates the Rabbids' ranks by donning a disguise consisting of a pair of Rabbid-style googly eyes on a headband, a sink-plunger loaded into his gun, and a lungful of helium. One of the senior Rabbids is on the lookout for Rayman, carrying the CD slip-case for the previous game as a reference image, and comes close to rumbling him — until Rayman lets loose a Rabbid-like manic "BWAAAHHH!", which dispels the Rabbids' remaining doubts.
In Mega Man Star Force, nobody seems to figure out that Geo Stelar is Mega Man unless he's explicitly transformed (Or changed back) in front of them. Combine the hairstyle, the voice, the eyes and the fact that Geo is close to the scene every time before and/or after something goes wrong would kinda make people think. In the anime, Bob Copper actually puts two and two together... and, in a moment of unbelievable stupidity, actually asks if Geo is one of Mega Man's groupies (Much to Geo's own surprise). In the same anime, when Luna finds out, she goes into a state of complete denial, despite the insistence of Bud and Zack and Omega-Xis showing up in front of them at times. Granted, her denial faded in the final episode of Tribe, but still.
City of Heroes features a mission in which your character has to infiltrate a Freakshow base. In order to facilitate this mission, you're given a disguise. What is the disguise? A rusty, spiky chestpiece (worn over your regular costume) and a bright red mohawk (ditto).
Early on in Final Fantasy VII, the characters disguise themselves as enemy troops to steal passage aboard a boat. For the most part, this works quite well, as Shinra troops are covered in head to toe with armor and baggy combat jumpsuits, but there are two major exceptions: Barret, the big black dude with a gun for an arm dressed as a sailor, and Red XIII, a cat/wolf-like creature who can't walk very well on two legs and whose tail sticks out of his uniform!
They actually play with it some in this case. Upon Arrival, one conversation option results in Mr. Gun Arm being described as looking like 'a bear wearing a marshmallow suit', and he ends up hogging up the bathroom looking at himself in the mirror, wearing said sailor suit, if he's not in your party. As for Red XIII... he dances back and forth from foot to foot, obviously having issues standing on two legs, but comments that he 'makes a pretty good human being' when you talk to him... after which he turns to the side, allowing you to see the tail (flaming tip and all) sticking out of his pants.
Done both ways in Team Fortress 2, depending on the team. Spies wear a mask that consists of the face of the class they're disguised as. If you're on their team, you can see them as a spy. If not, well, it's a perfect disguise (until the shooting starts).
Maria in Silent Hill 2. Although more intricate than "standard" Clark Kenting (clothes, hair, cosmetics, vastly different personality) James once mentions that she looks a lot like Mary then never mentions the resemblance again. Heavily justified though in that not only is James completely batshit insane but it isn't really Mary at all, merely a construct James has invented due to among other things his refusal to accept her death. Yes, it is a very strange game.
Yeager in Tales of Vesperia does this when he disguises himself as Regaey. Granted, the name was a dead giveaway, but his demeanor as Regaey was very meek compared to his actual personality.
Lego Star Wars II: Stealing a Stormtrooper's helmet is enough to fool the Death Star's stormtroopers and security systems ...even if it's Chewbacca, whose head cannot fit into said helmet.
The trope is an essential part of the Hitman series of games. Walk calm, wear the right uniform and carry the right gun in the right way (ie. out-of-sight or in off-hand). Otherwise, trouble.
The second game actually subverts the trope: disguises consist of a simple uniform and sometimes (Russian levels) a hat. It doesn't matter if someone sees your face, getting out of sight and changing uniform will fool that guy, even though your face is clearly visible. There's one exception: the Japanese levels. Guard uniforms here include a balaclava and NV goggles but despite these and the fact that it's night, the snipers scattered around the level WILL recognize you.
Zigzagged in Hitman: Absolution: disguises will fool regular people but if you run into anyone who is wearing the same clothes as you, they will immediately notice you're not one of them, even at believability stretchingly large distances. The only way to avoid this is to use an "instinct" draining special move that causes 47 to...keep his head down.
In Alundra 2, it is obvious to the player that the Pirate Queen's bodyguard is Flint's father, but Flint and everyone else can't see it. His outfit and hairstyle are unchanged from the last time Flint saw him, the only difference being the addition of a mask.
In the Dating SimTrue Love, the famous Idol Singer Sonoko Takahashi, who has her face plastered all over posters and CDs around town, is able to pass herself off as an ordinary New Transfer Student to the PC's high school by simply putting her hair up, wearing glasses, and going by the alias of "Ryoko Shimazaki"...which happens to be her actual birth name. She comes under no suspicion by any of the students she interacts with other than the PC, and the PC only begins putting two and two together when he sees her without her glasses on.
In Trials & Tribulations, Elise Deauxnim is (as you can probably guess from the name) another, previously mentioned character in disguise. Said disguise consisted of changing her name, wardrobe and hairstyle. She does nothing to conceal her face, and she hasn't aged very much since she was last seen. What makes this curious is that her own daughter, Maya was able to recognize her face from a photo earlier in the series, but doesn't do so now.
Parodied in the "Punyverse" arc of Sluggy Freelance. As a Running Gag, characters keep noting, "Who would have thought that Princess-Princess is the secret identity of Secret Angel Princess Princess-Princess? Boy, that sounds stupid when I say it out loud."
Lampshaded in Smithson. Micki has met both the local superhero and his alter ego, Chuck, but hasn't figured it out yet, despite having seen Chuck without his glasses. Chuck is astonished at that.
Happens in El Goonish Shive, to the point where Tedd can fool Will and Gill without even meaning it — they call him an impostor when they see him without his glasses. To be fair, though, those are really big glasses and they seem not to know what glasses are.
Also massively parodied with an incredibly lame (but apparently successful) government campaign to hide the presence of aliens on earth by such methods as having them wear T-shirts that say "Homo Sapiens".
More recently, Rhoda used this to hide from people harassing her following her appearance on the TV News the day Pandora appeared. It worked, both on fellow students and on at least a few readers.
Parodied in the "superhero fantasy" arc of Boy Meets Boy: one character points out that Foxman's roommate Collin looks identical to his nemesis His Mind Kills, but wholeheartedly accepts Foxman's explanation that they can't be the same because His Mind Kills wears goggles.
Played straight in Girl Genius when Agatha, Wooster, Zeetha, and Krosp ride right in through the gate of Mechanicsburg just after a giant hologram of Agatha has been seen and discussed from as far away as China with Agatha wearing no disguise of any kind, instead relying on the cover story they came up with. Only von Mekkan figures it out and because the Castle rather blatantly points her out, even the fake Hetereodyne doesn't notice.
In Mechanicsburg's defense, there's a big difference between "discussed" and "discussed accurately". And Agatha wasn't wearing that dress...
Bad Guy High has SuperDan, whose costume is him putting on a cape.
Parodied and subverted in Fans! when one of the main characters notices the obvious similarity between new superhero Hyperman and up-and-coming reporter Lance Clarkson. When she confronts Clarkson about it, it turns out that they aren't the same person, and that Clarkson has been playing it up to make people think that they are.
Parodied and subverted in PVP. Two characters are speculating on the identity of LOLBAT, when one suggests it's Rex Roffle and another says that's obviously silly. Besides the obvious Meaningful Name, he looks and acts just like LOLBAT, complete with the mask. Then, the next day, we find out that LOLBAT ia actually Butler, so unless he's keeping up three identities, Rex Roffle is just a random Identical Stranger.
Everyday Heroes has Uma and her father (aliens stranded on Earth) disguise themselves by wearing glasses and doing their best to blend in with humans... despite the fact that they resemble cows.
Parodied in Captain Excelsior, where everybody except superheroes and supervillains can see through the disguises.
And we're not even talking about Paper-Thin Disguise here, even a hint of a mustache on a superhero who usually doesn't have one makes him invisible to other supers.
Parodied in The Adventures of Dr. McNinja, where the Doctor attempts to disguise himself as a different doctor by... pinning his name tag on his coat. While still wearing his ninja mask. Nobody is fooled.
Captain Broadband keeps a Secret Identity Costume on him at all times (plus a Sidekick Gimp costume for his sidekick). He's yet to use it though.
Robin cannot for the life of her figure out that Amber is Amazi-Girl, in spite of the fact that it's not even a secret. She is, instead, convinced that Ultra-Car—who is exactly what he sounds like—is Amazi-Girl. The insane lack of sense this makes is lampshaded regularly.
Meanwhile, in the Alternate Universe of Dumbing Of Age, Amber does keep her identity a secret, with Danny in the Lois Lane position. She begins to ruffle her hair and lower her voice as Amazi-Girl to maintain the secret. This isn't an issue for the other characters, though—those actively pursuing Amazi-Girl's secret identity have no idea who Amber is, and Amber's closest friends don't seem to be aware of the masked vigilante on campus.
Kiwi Blitz. Averted. The media quickly begins to theorize that Steffi is Blitz, pointing out they physically resemble each other and that Kiwibot is similar to other mechs built by her father.
Subverted in Princess Chroma. The main character's magical girl costume is a poor disguise and absolutely nobody is fooled by it no matter how much she insists she and "Princess Chroma" aren't the same person.
Rip Haywire manages to be unidentifiable to his long-time girlfriend Cobra simply by wearing an eyepatch... acceptable as it's an Affectionate Parody of action-adventure comics.
Justified in Sailor Nothing — one of the Magical Girl powers they possess is an inability to be recognized unless someone thinks about it really hard.
Played straight and subverted with Dr. Horrible's Sing-Along Blog, in which, while Penny apparently does not recognize Villain Protagonist Dr. Horrible as her laundromat buddy Billy, his Arch-Nemesis Captain Hammer does, likely from having seen his video blog, and uses this opportunity to ruin Billy's life even further by trying to steal Penny, the girl that he loves.
Penny finally 'mistakes' Dr Horrible for Billy the end when she is delirious and near-death, leading her to reassure him with the painfully ironic line, "Captain Hammer will save us".
Shadow Hawk of Epic Tales may have a full body costume, but he uses his birth name as his superhero identity. His logic is that it's such an obvious connection, that people will think it's too obvious. So far everyone who has met both of his identities has been able to figure it out, as well as a few who have only met one of his identities, but know of the other.
Subverted in the Whateley Universe stories. In the beginning of the third Phase book, on the first day of school at the Whateley Academy, the headmistress Mrs. Carson gives a speech to the new students. Before the end of the talk, Phase has figured out that the headmistress is also the superheroine Lady Astarte. By the end of the book, Phase has figured out that Mrs. Carson is also a former superheroine of the 80's, Ms. Might. By the end of the fourth book, Phase has figured out that the early-thirties-looking Mrs. Carson is actually in her mid-seventies and has had at least two other superhero identities over the decades.
Coach Z actually tries to convince everyone that he is both Damp Towel Man and his creatively-named secret identity, Dan Towelman. As usual, nobody cares.
Parodied in Cow and Chicken. When anyone entertains the thought that Cow and Supercow could possibly be the same cow (being the only two sapient cows in the Universe no less) that idea is always shot down by the fact that Supercow speaks Spanish. In one episode, the Big Red Bad almost figures out that Cow is Supercow, kidnapping said bovine while she's out of costume. Chicken wears the costume to rescue her, leading Red to conclude that Cow can't be Supercow.
Averted in the 2002 revival, where He-Man looks nothing like Adam. Other characters still often notice Adam skipping battles, but instead think he's a coward who's been running off to hide.
His sister was pretty much the same. The only real physical difference between Alura and She-Ra was a change of clothes that was barely a disguise at all. And seeing as Alura was an Action Girl in her own right even by herself, you kind of got the feeling that the Evil Horde was kind of dumb.
Fisto: Hey, Mekaneck, what's Prince Adam doing fighting Modulok, all shirtless and glorious?
Mekaneck: That can't be Prince Adam, Fisto. Prince Adam's giant green cat doesn't wear a mask.
He-Man himself noticed this in the DC Comics miniseries that preceded the cartoon; when He-Man arrives to the palace in search for a magic amulet, and then the King wants to meet the hero of Eternia, He-Man wonders what, besides his garb, could prevent his father from recognising him. Luckily, he doesn't.
Bugs Bunny can fool anyone who was just chasing him by hiding his ears and tail, even though he's still a six-foot gray-furred rabbit. They may be distracted by other things, however.
The Beagle Boys in DuckTales, who walk around with their masks still on.
Speaking of DuckTales, there was an episode when the triplets tried to figure out Gizmo-Duck's secret indentity. Fenton was offended when they got it wrong. That didn't even tip them off.
In another episode, Scrooge himself takes up a superhero identity, only to have a Jerkass reporter ruin it by showing apparent footage of said hero turning to crime. No one notices that not only is this costumed duck not the same one, but it clearly is the reporter instead.
Lampshaded in Superman: The Animated Series when Supergirl attempts to disguise herself with a pair of glasses and a wig — Superman/Clark Kent sees right through her Paper-Thin Disguise despite the fact that it's a more elaborate disguise than Superman himself uses. Well, Superman/Clark Kent does have X-ray vision...
Lana Lang outright averts this trope in the DCAU; one of her questions to Superman at their "first meeting" is whether Martha made his costume. Lois plays it straight as an arrow, though. (Lana had an extra clue Lois didn't; she knew Clark had superpowers because he demonstrated them to her in the pilot.)
Transformers are sometimes guilty of this. Not only do some robots have parts of their alternate modes easily identifiable in robot mode, but often their faction symbol is visible even in their alternate mode, and this doesn't seem to be a dead giveaway, even to those who know what the symbols mean.
Sources indicate that at least some of the fiction-writers (comics, cartoons) would like to have the disguises actually be disguises, but Hasbro demands that faction symbols be visible in both modes as a form of "brand recognition" (read: Viewers Are Morons). In fact, the only Transformers toys that didn't have blatantly obvious faction logos in alternate mode were those from the Alternators toyline, which was based on licensed cars (and most of them still sported faction logos on their license plates anyway). Imagine if DC Comics would insist on having Clark Kent wear a Superman "S" somewhere on his clothes so he could be easily recognized by readers/viewers/buyers (in the case of action figures)...
Interestingly, in the Generation 1 episode "Making Tracks", Tracks disguised himself as a regular car by making his Autobot symbol invisible. Makes you wonder why none of the others ever thought to do that.
In the third episode of the original series, the Autobots decide to set up an ambush for the deceptions. Hound uses his holographic projector to make a fake "rocket base" and the Autobots will be in it, under disguise, to attack the Decepticons when they show up to raid the base. What disguise do the Autobots go for? If you guessed "In their car mode in the base's parking lot." Congratulation, you're smarter then an Autobot. They decide to don labcoats and pass for the human scientists. Despite the fact that even the smallest of them is twice as tall as a human and about 3 times as wide. And made of metal. With shoulder-mounted guns. Yes, that plan failed.
With all this talk about symbols, it's easy to forget that many of the vehicle modes themselves are obvious giveaways. On the reasonable side of things, Prowl and Streetwise become the only Japanese highway patrol cars in the United States. At the opposite extreme, Blast Off is a ludicrously undersized undersized purple and olive green space shuttle orbiter, a disguise that can only be made worse by the addition of Decepticon symbols.
And it gets better/worse. In an episode of a Japanese version of Transformers, Optimus Prime tried to disguise himself as a Budha statue.
Undercover Elephant on CB Bears wore disguises that primarily relied on a single prop (a chef's hat, a pink tutu, etc.) and a thin ribbon-mask. They nonetheless worked, at least until his sidekick Loudmouse "blew his cover"... despite being, well, an elephant.
Mercilessly parodied in the Animaniacs shorts of Chicken Boo. Despite his ability to masquerade as anything from a rocket scientist to an idolized leading man movie star with a pair of glasses or a wig and appropriate clothing, he is a 6-foot-tall not-anthropomorphic-at-all rooster that talks only in clucks. Attempting to blend in with humans in this fashion, he succeeds perfectly (with the exception of one derided outcast in each cartoon that keeps saying he's just a giant chicken), until his disguise falls off, at which point he is driven away by screaming mobs.
One of the few segments that altered the scenario ever so slightly was a crossover between "Chicken Boo" and "Katie Ka-boom", a girl who has very violent moodswings. In this episode EVERYONE except Katie herself is able to see that her boyfriend is actually a giant chicken. This results in her turning monstrous when her parents tell her this, not believing them until the end where Boo's disguise is removed... at which point she turns monstrous again and destroys the entire house, sending Boo flying because he didn't tell her he was just a chicken.
The penguin Feathers McGraw in the Wallace & Gromit short "The Wrong Trousers" disguises himself as a chicken by wearing a large red rubber glove on his head.
Despite wearing her Jem Star Earrings in both of her identities, no one expects the mysterious Jem to be Jerrica Benton—must be because of the pink-colored '80s Hair she gives her rock-star identity. Or because of Synergy's ability to use holograms to show Jem and Jerrica in the same place at the same time.
Beyond the hair, the two still look nothing alike, Jerrica's face is rather simple and plain looking, while Jem's is much more detailed. Although they have the exact same voice.
Eponymous Invader Zim has a disguise consisting of a pair of contacts and a wig (which is completely solid and doesn't move at all) that manages to fool everyone but Dib. Partially justified in that in the entire series there are maybe half a dozen characters smarter than a sack of hair.
There was an episode where he lost one of his contacts in front of a crowd of classmates, revealing his red compound eye. People were suitably shocked, until he explained it away as a very bad case of pinkeye.
Also happened in reverse with the Irkin fry cook lord Sizz-Lor. He wore a gas mask while kidnapping Zim and then proceeded to take it off. Zim didn't recognize Sizz-Lor at first (even after he put on an apron with his name on it) until he put on his little white fry cook hat.
There was also an episode wherein two aliens tried to abduct Zim. Their disguises were worse than his (if that's possible), and not even Zim was fooled.
Becky Botsford is WordGirl, but nobody, not even her friends and family realize this (except once or twice; still long after they should've realized it). Even though she has the same height and build, and she doesn't cover her face at all.
The show, being an Affectionate Parody of superhero cartoons, goes out of its way to parody this, too. Becky's friends and family are constantly commenting on how Beck "just missed" seeing Word Girl, or that she sure looks a lot like her, etc. One villain, Tobey, actually even caught on right away when he was introduced to Becky and purposefully put her in a situation where she had to reveal herself—but she sent her monkeysidekick out in her costume instead, and Tobey saw him from a far enough distance that it looked like it could have been the real Word Girl. In the episodes after his introduction he constantly hints to Becky that he still believes she's really Word Girl—he just has no way to prove it, considering he supposedly saw them together in the same place.
Until the episode, "By Jove, You've Wrecked My Robots!" where Tobey outright accuses Becky of being WordGirl with plenty of evidence- thanks to, well, this snapshot◊. As Tobey said, so many other things fall into place once you have evidence like THAT (same height, same hairstyle, same ruby red lips...).
She's constantly calling her parents 'Mom' and 'Dad' when she sees them 'as WordGirl,' then painfully acting as if she meant to say something else ("Mom! I mean, mom... Mambo!").
Too many examples to list here, really, but my favorite is when "Exposition Guy" inadvertantly throws a newspaper featuring WordGirl at Becky, and her face pokes through- at the exact place her face would be in costume, right size, everything.
In the Comic Book Adaptation, Mr. Big suggests that WordGirl's secret identity would be revealed if they could only remove her hood - The same hood that doesn't even cover most of her hair.
It reaches a point where Becky is about to sneak out as WordGirl and her father catches her, only he thinks she's just playing by dressing up as her.
From Gargoyles: The Hunters wear a mask with three large red diagonal slashes across the face. The original Hunter, Gillecomgain, has three large diagonal scars across his face courtesy of Demona, which is the reason he Constantine chose the symbol. Macbeth, who knows and bears grudges against both, is completely shocked by the relevation that they're the same guy, despite knowing that Gillecomgain has three scars on his face and the Hunter has three identical scars on his mask.
Averted by later Hunters, including Jason, Robyn and Jon, as they don't have facial scars and use different accents when not masked.
Gillecomgain didn't invent the idea behind the Hunter's Mask, either; Constantine did. (To be more precise, Constantine was so impressed by Gillecomgain's ardor in destroying gargoyles that he used Gillecomgain's face as a model for his own symbol of anti-gargoyle terror: painting his head almost entirely black, with three red stripes across the face.) It wasn't until later that Gillecomgain used the black executioner's mask with the three red stripes, which was modeled after Constantine's face paint.
Parodied in Drawn Together. When Captain Hero adopts his "Secret Identity", Tim Tommerson, the only change he makes is to put on glasses — he doesn't even remove his costume. That said, Tim Tommerson and Captain Hero were seen in the same room and kissed each other in the two part finale.
Parodied in the "Pie Man" episode of The Simpsons, "Simple Simpson".
Marge: I knew it was you all along. Homer: Was it the [Spider-Man parody] kiss? Marge: No, it was clearly you in that costume! I mean you would have to be an idiot not to see it from the start.
Also, earlier in that episode, Lisa says "Dad, you're clearly the Pie Man. We've been getting his mail for weeks."
There was also the episode where Homer was making up conspiracies and posting them on the internet. The homepage showed a picture of Homer with a black bag over his head with a white "X" on it. The bag and the shot of Homer are seperate pictures, and at one point Homer's face is visible for a second before the bag loads. Later when Homer tries to reveal himself at a press conference, nobody believes him until he puts the bag on in front of them so they can see the resemblance.
Within the comics this trope is played with using the ficticious comic book hero Radioactive Man. One of the man's distinguishing features is a large lightning bolt-shaped piece of shrapnel sticking out of his head, therefore when he is in civilian clothing he must hide it by constatly wearing a hat - the other characters hardly ever acknowledge this.
The eponymous hero of Danny Phantom, Danny Fenton. White hair, a jumpsuit, different-colored eyes, a tan, and a shared first name do not a good disguise make, kid.
There might be some justification for this, though; no one thinks its even possible for Danny Phantom to have a human form, since he's a ghost and...well, dead (supposedly). Thanks to duplication machines and shape-shifters, Danny Fenton and his ghost form have been seen together.
Also, Danny is seen as a Straw Loser by almost everyone, not unlike some versions of Clark Kent; it's hard for them to picture him as being anything but a regular, unimpressive guy. When he's Brought Down to Normal in the Series Finale and tries to save the local Jerk Jock from ghosts, the jock derisively asks if he thinks he's Danny Phantom.
Teacher's Pet is about a dog who dresses as a boy and goes to school, and nobody notices he's a dog.
Peter: All he did was change clothes and put on a pair of glasses! Some disguise! Winston: Hey, don't knock it, man. It works. Peter: Let's hope Dr. Destructo's near-sighted.
Parodied in the Superhero Episode of Futurama where Fry, Leela, and Bender become superheroes. Somehow the public does not realise that the only one-eyed woman with purple hair in the entire city of New New York is, in fact, the one-eyed purple-haired superheroine Clobberella. Even her own parents are fooled.
This is made even more blatant by the fact that Leela and her mother are the only purple-haired female cyclopes in the entire universe.
Teamo Supremo's leader Captain Crandall never really changes his appearance between his superhero and civilian identities, costume aside. This makes one wonder how his own mother can't seem to put two and two together and figure out why there's some superhero running around who looks exactly like her son, though in the last episode it's revealed she's been aware of him being a superhero the whole time.
Captain Caveman. His segments on the early 1980s The Flintstone Comedy Show, featured Cavey working alongside Wilma and Betty at the newspaper "The Daily Granite" under the guise of Chester, the copy boy. Cavey's "disguise" consisted of a pair of glasses, a bow tie, and speaking in a higher-pitched voice... and that's it. Apparently nobody suspected the only two guys in Bedrock resembling walking hairballs, Chester and Captain Caveman, of being one and the same (with Wilma and Betty criticizing Chester for his clumsiness and telling him he "should be more like Captain Caveman").
The Crimson Chin does it better. He wears glasses and a hat... over his mask, and does nothing to hide his comically large Lantern Jaw of Justice.
Said glasses are not even on his face, but sit on his huge, jutting chin.
The show also parodies this when Timmy puts on a mask in one episode involving Catman where every time he puts it on, Catman can't recognise him as his sidekick. Despite actually watching Timmy put the glasses on. This is much to the annoyance of Timmy, with Catman going "Where did X go? X, you're back!" or something similar.
The SWAT Kats used to work for Commander Feral, but he can't figure out their identities. It's even worse when you realize that they work at a salvage yard owned by Feral and use his throwaways to save his tail.
Possibly justified in that Feral is shown to have next to no interaction with the SWAT Kats in their civilian identities. He put a pair of pain in the butt cats in charge of making sure they're working at the salvage. Also, Feral commands many pilots, which likely include some hot shots and almost certainly include some that don't like him personally. The Kats also had to refurbish or build their jet and tools from scratch; a minimal amount of time would have to pass between Chance and Jake being railroaded to the junk heap, and T-Bone and Razor heading for the skies. Time can mean forgetfulness.
The person who is really stupid for not figuring things out is Deputy Mayor Calico Briggs. She's the inside contact for the Kats, and they constantly save her tail. Their civilian identities run the garage where 'Callie' gets her car worked on, and she often chats with them when dropping off or picking up her car; the Kats don't even change their voices for her. Even the difference in physical appearance granted by uniforms vs coveralls doesn't explain it.
The real kicker in Callie not figuring out their identities, is that she makes several obvious hints that she is actually attracted to Jake/Razor in both his civilian and SWAT Kat identities, yet can't seem to piece together the mechanic she likes, and the ace pilot she also likes, could be the same guy.
In Mighty Orbots, geek inventor Rob Simmons is also the leader (and pilot) for the eponymous Combining Mecha. His costume change consists of simply removing his glasses and swapping his lab coat for a flight suit.
Lilo & Stitch. Have you ever seen a blue dog, or a tourist with four eyes?
Stitch, however, does get questioned by Nani and the petstore owner. Myrtle also doesn't seem to quite buy the "dog" story, either. It's Jamba and Pleakly who follow this trope.
Parodied on Tiny Toon Adventures in an episode where Babs became "Super Babs". At the end of the episode, the boys realize that Super Babs might be someone they know, and start trying to figure out whom; after a pause, Plucky turns to the others and says "Who do we know named 'Super'?"
Parodied in El Tigre, where Rodolfo's civilian guise is the outfit worn by Clark Kent in the Fleisher Brothers Superman cartoons. And worn over his costume, including his mask.
Oddly enough, he can't recognize Perry if he were wearing anything else. Like when he showed up dressed as a plumber:
Doofenshmirtz: (Perry removes his mustache) "A platypus plumber?" (Perry puts on his hat) "Perry the platypus plumber?" (Perry removes his tool belt) "*gasp!* Perry the platypus!"
The hat also tells Doofenshmirtz it's Perry, even after he and Candace switched bodies!
Lampshaded in the tv movie "Across the 2nd Dimension," when Doof-2 actually points out, and attempts to teach his counterpart the fact that just because the hat is removed, it's still the same platypus.
Prehistoric Doof had the same problem with Prehistoric Perry, who wore an animal skull instead of present time Perry's hat.
The trope is somewhat justified when it's revealed there were several platypuses, platypi, platypeople, well, you get it, in Danville and Phineas had to take a closer look at each one of them before telling if Perry was among them.
Despite this, in the tv movie, knowing Phineas and Ferb's platypus was named Perry and seeing said Perry fighting "so good" weren't enough clues for him. An annoyed Perry had to put on the hat. Doof-2 believes this to be the reason Doof-1 never took over his Tri-State Area.
Doof once programmed an inator to defend itself against Perry and supplied it with all his knowledge of Perry. Perry tricked the inator by removing his hat.
A hunter once handcuffed Doof to a hatless Perry and Perry was the only one to see that as an Enemy Mine case since Doof once again failed to recognize Perry.
Phil and Lil from Rugrats can fool anyone by just putting the ribbon on Phil's head, or removing Lil's ribbon, despite the fact Phil wears pants and Lil wears a dress.
When the Chameleon starts impersonating Spider-Man. While most people are fooled, Captain George Stacy smells a rat, noting that the guy claiming to be Spider-Man is too tall and broad to be the legitimate web-slinger.
Stacy also positively recognizes the real Spiderman despite his new black symbiote costume because his body type and mannerisms match those of the genuine hero. And when Venom shows up, he immediately notices it's not Spiderman due to the different body types.
Played With on South Park: it's rather obvious that Professor Chaos is really just Butters wearing aluminum foil, but the only person who figures this out is Dougie. His parents and Stan have also seen him in his getup, but just don't seem to care.
Later, when the other South Park boys play superhero their identities are also fairly obvious, except for Mysterion. However, he's the only real superhero anyway; everybody else just correctly sees a bunch of kids playing. Captain Hindsight is a straighter example.
Spoofed in an episode of American Dad!, where Roger ends up with one of his personas developing into a split personality. To convince "Sidney's" girlfriend that he's Sidney, he puts on glasses and sweeps back his hair. He even does this while turned away from her, resulting in the girlfriend getting confused and asking where Sidney went.
YMMV with Tony Stark in Iron Man: Armored Adventures, as no one seems to suspect that the guy that is smarter than all of Stark International could have had his hands in creating an advance suit of armor. Howard even come out and states that he knew his son was Iron Man because no one else could have come up with the designs.
As far as the main characters of The Incredibles are concerned, putting a mask on that hides your eyes protects your identity.
Young Justice has Superboy...turn his shirt inside out for his civilian identity. Not only does this hide him perfectly, but no one even wonders why Conner always has his shirt turned inside out. Since the show averts it otherwise (most of the kids don't have civilian identities, and those who do wear masks), this is probably an homage to the trope namer.
Superboy may get a pass because the Team's activities are supposed to be on the down-low and not public knowledge. He's seen helping Superman in public at least once, but that's in the middle of a crisis and far from where Connor attends public school. Speaking of school, on his first day of high school a lot of the students were wearing various superhero shirts themselves, including Superman's shield. If Connor hadn't reversed his shirt he still would have fit in.
W.I.T.C.H. solves this problem a number of ways. Most of them include fighting their foes in other worlds or, if they have to do so on Earth, fighting at night. As early as the second episode, we see that Caleb's able to realize that Will was the same girl who tried to push back Cedric from entering Earth, despite her smaller build in her normal self. Though, the series finale implies that their Final Fight with Cedric lead to some people possibly figuring out who was who.
Atomic Betty: Sparky wouldn't recognize The Scribe as "Milton Scrivener" until the scribe took off his mask and put on "Milton"'s glasses.
Yogi's Space Race: Granted, "Captain Good" and "Phantom Phink" couldn't look more different unless they had different genders but, the two of them officially enter the same races and nobody finds it odd they're never seen together even when the races were about to begin. Well, they do find it odd but not enough to suspect they're one and the same.
In one episode of Darkwing Duck, Darkwing goes to a planet filled with superheroes. Obviously, this means everyone wears a brown suit and glasses over their spandex, even though all of them know that everybody else on the planet is a superhero. They also are shown they would be Too Dumb to Live if they weren't all invulnerable.
In the television version of Static Shock, while Static's mask does cover a fair amount of his face he does have a pretty distinctive hairdo, yet almost no one seems to make the connection, even characters like Hot Streak who bullied Virgil and later became Static's enemy, too. The only one who does is Talon who's following Richie to try to figure out who Static is. The hairstyle is justified by Ebon who points out a lot of guys wear their hair that way. Talon counters by pointing out he's the only one who does and hangs out with Richie. His own sister doesn't figure it out until she actually sees Static in her neighborhood. At one point one of his friends even goes so far as to mention (out loud, but to herself) that she never sees Virgil and Richie at the same time as Static and Gear and starts to wonder if maybe they're the same people, but quickly dismisses the thought as ridiculous.
Jay Leno and Jimmy Kimmell pulled this off by disguising themselves as reporters.
Jimmy Kimmell's cousin once snuck into Super Bowl media day simply by dressing up in the uniform of Carolina Panthers Kicker John Kasay. It worked, because of all the hundreds of reporters who covered the event, none actually knew what Kasay looked like.
An rumor spread by his detractors says that because of the controversy surrounding his election, Abraham Lincoln dressed up as an old woman for his own safety to get through Baltimore on the way to his inauguration. Maryland was a pro-slavery state where Lincoln was incredibly unpopular, and there were reliable reports warning of an assassination plot. Since he was 6'4", he had to hunch over to pull this off. In reality he did wear a slouch hat and overcoat in a failed attempt to appear less obvious, but he did not disguise himself as a woman. (In a Brick Joke, at the end of the war Northern supporters falsely claimed that Jefferson Davis was captured while disguised as a woman).
Most of Sacha Baron Cohen's characters are this. Like Borat, which consists of a mustache and accent.
Harold Lloyd, an inspiration for Clark Kent, found that if he took off the stage glasses of his most famous film character, no one recognized him.
That's because he showed up as himself, i.e. the film actor Charles Chaplin, without the costume or the mustache (he never actually grew such a mustache, it was always a stick-on). Everybody knew who he was and had a nice laugh.
A documentary on spying had a section regarding disguises and how they're used, with a former CIA specialist explaining how simple disguises can work wonders if you play on observers' expectations. As a demonstration they had people assigned to trail a blonde woman dressed in jeans, a hoodie, boots and a ballcap, carrying a backpack. The woman faked drinking a lot of water and thus had a reason to duck into a bar to use the bathroom. While they were intently observing the bathroom and the back alley door, they never noticed the brunette wearing a little black dress, heels, and carrying a small purse who strolled out the front door on the arm of the man who'd been waiting for her.
An inversion occurs with pornstar Eva Angelina in that her glasses have become so synonymous to her general appearance that she's gone to conventions without them and wasn't recognized at all.
Comedian Groucho Marx painted on his famous mustache with grease paint for most of his career. He was surprised to find a large crowd of fans who had gathered to see him at a train station completely ignored him when he got off the train. Realizing what had happened, he ducked into his car and smeared on a grease paint mustache, and was instantly recognized. There is even a story (probably apocryphal) about Groucho house-sitting for a friend in Beverly Hills. He was taking advantage of the swimming pool and had the cops called on him by the neighbors. No one would believe he was Groucho Marx without his mustache.
Reportedly, Marilyn Monroe would employ this with a curly black wig, a pair of sunglasses and some loose-fitting clothes. She was also apparently very good at changing her body language in public, to the point where she was able to walk completely ignored in a crowd — until she fluffed up her hair and struck a pose, and was instantly swarmed.
"Do you want to see her?"
Many decades ago, photographs were rare and hard to produce, and people with the artistic skill to do a composite sketch were scattered much further apart. Thus a fugitive could reasonably move to another place without notice. The Wanted Poster was less effective than it is usually played to be; criminals on the run were often chased by former acquaintances, the only people who could recognize them.
Aviator Charles Lindbergh actually used the alias of Careu Kent when visiting his secret second family in Germany.
Shakira went unoticed in public for a couple of months by wearing modest clothing, going by her middle name and wearing a baseball cap.
The use of a fake distinguishing feature such as a scar can make people focus on the scar so much they don't notice any other real details.
Eric Morecambe, at one time half of the most famous comedy double act in Britain, used to get by in public by taking his trademark glasses off and affecting a limp. His son has stated that this worked so well he wouldn't even get recognised by people sitting next to him on trains or planes.
Many models can have relatively normal lives by simply wearing minimal or no makeup, pulling their hair back into a simple hairstyle like a ponytail, and wearing some reasonably conservative clothing. Since most people see them professionally made up, and often in photoshopped images, it's easy for them to be less noticeable. There are models who've walked into their agency's offices, with pictures of themselves plastered all over the walls, and not been recognized by the staff because they've been in casual clothing and not posing.
For nude models and porn actresses, often merely wearing clothes suffices to make them unrecognizable.
Jewelwent onstage at a Karaoke bar as 'Karen', wearing a wig, glasses, and false nose, and was unrecognized. (A few people even called her 'homely'.) She sang a few of her own songs, to acclaim from the crowd. She then stripped off the disguise and went back in as herself and sang a few. No one made the connection. Admittedly, it was dimly lit.
Murderer Ted Bundy was able to walk around in broad daylight for days while a wanted fugitive whose face was plastered all over TV. The only attempt he made at a disguise was drawing a mole on his face with a marker.
Anybody who's ever worn glasses for years and then suddenly switched to contacts (or vice versa) knows that you can look like "a whole different person." Glasses come with a very specific set of cultural stereotypes, which are completely destroyed when you get rid of them.
Same thing with, say, wearing a substantial amount of makeup regularly and then suddenly appearing without it.
Or shaving off your facial hair.
PokerStars once challenged tennis star Rafael Nadal to bluff people into believing that he wasn't Rafa with only a pair of glasses and a golf receptionist's uniform as a disguise. He didn't succeed.
This is the essence of other tropes like Clipboard of Authority. Attitude and body language matter as much as clothing or make-up. If you act like your role, then people assume you really are your role. Discussed further in articles like "How to Sneak Around."
This is more intricate than most examples of this trope, but scientists have developed a wearable device that prevents facial recognition cameras from recognizing the wearer. It's a pair of glasses.
One interviewer accompanied Mel Gibson to the DMV, with only a baseball cap as a disguise. He then watched Gibson visibly "turn off the charm" and become so inconspicuous that only the ID photographer noticed a vague similarity.
Tory went with the glasses disguise and failed miserably.
Kari noted that wearing a full costume makes a person a little too suspicious, as if you're trying to hide. Adam, a noted cosplayer who made a game of playing hide and seek by wearing full costumes at each SDCC, found this out the hard way when someone recognized him straight after just donning his cosplay and exiting an elevator.
However, Kari then noted that wearing a cap was sufficient enough to fool everyone (she even fooled Grant and other friends when she walked the floor wearing one).
Adam himself told on the show that he is more recognized on the street when he is together with Jamie, because while people can recognise his features, it's Jamie's trademark dressing style that takes the spotlight.
"I MAY be that guy from that show, but he IS that guy from that show."
Tyra Banks once did this live and in person on an episode of the Today show. Without makeup or hair styling, while walking with a slump and wearing a pair of glasses, she went into the crowd outside the Today set's window as a "production assistant" to ask people about their opinions about supermodels and Tyra Banks in particular. After a couple of minutes of absolutely no one realizing it was her, Banks pulled her hair back, straightened her posture, took the glasses off and suddenly ''became" Tyra Banks, Supermodel. The crowd loved it.