Postal Worker: Okay Mr. Burns, what's your first name?
Homer: [beat] ...I don't know!
This trope is when a character, in disguise or otherwise pretending to be someone else, doesn't know some basic piece of information about the person they're pretending to be. This could be because they didn't research the identity enough, or maybe the disguise and cover identity were done in a rush and they didn't think all the way through.
A quick-thinking character might be able to bluff their way out of the situation, either through a Line-of-Sight Name, using their Real Name as an Alias, or simply pulling the Bavarian Fire Drill. This can backfire if they say the wrong thing, mess up the Trust Password, or if the person they're trying to fool is already suspicious. Otherwise, Hilarity Ensues as the character either tries to play it straight (i.e., they've somehow ''forgotten'' their first name, birthdate, hometown, etc...) or just tries to awkwardly escape. In drama, this might lead to a tense situation where the character is found out and has to escape without being caught.
Compare Stereo Fibbing, for when two characters have to make up a lie on the spot to get out of this situation.
- Kamen no Maid Guy has an example where the twenty-something Ninja Maid Tsurara tries to infiltrate Naeka's school as a student. The usually ditzy Naeka asks her which Eastern Zodiac year is her birthday in. For people in heavily Chinese-influenced country, your own zodiac year is something you already know and can be answered without thinking. Calculating your supposed birth year from a fake age and come up with zodiac year for it, though, would take several seconds and some finger-counting.
- In Lupin III: Dead or Alive, Olèander is able to see through Lupin's disguise because of how it felt to kiss Pannish. In the Dub, Lupin jokes he needs more practice. In the Sub, it is because Pannish never smoked. She doesn't seem upset about the disguise, and continues to work with him afterwards.
- Naruto: Team 7 tries their utmost to avoid this when they have to meet Sasori's spy whilst disguised as Sasori. It actually works; the spy doesn't realize he's dealing with an imposter... he was just intending to double-cross Sasori anyway.
- In the early 1990s Spider-Man arc where Peter Parker's parents returned from the dead, May realized they were imposters when they refer to the wrong date for their anniversary, indicating that they somehow didn't know about their secret wedding several months prior.
- Happens twice in Paperinik New Adventures:
- When a group of Evronians (who just don't get the point of many expressions of emotions and tend to ignore them) disguise themselves as Xerbians to trick Xadhoom into wearing a restraining device they have no idea of what a Xarghon is. A Xarghon is a traditional Xerbian welcome dance that any child on their homeworld would have known about, leading to Xadhoom (who really loves dancing to boot) to see through the ruse... And amuse herself with their attempts at guessing what a Xarghon is before she blows them up.
- When Paperinik infiltrates Belgravia disguised as Grigorji Grimka, son of the president, to try and find out who in the government betrayed and tried to kidnap him, he was not informed that Grigorji had a large and irascible fiancee who is allergic to flowers and he doesn't like, thus allowing her to see through his disguise when he's nice and offers her flowers (thankfully she wasn't the traitor and limited herself to see who the impostor was and why he was there, leading a group of loyalists to the rescue at the right moment). This is caused by Grigorji, who is an idiot, purposefully leaving this detail out alongside the fact he keeps two lions as pets while telling his lover, who is actually one of the traitors, that he's still in America and the Grigorji coming home is an imposter.
- In a Supergirl Annual, the titular heroine tries to pass herself off as Lana Lang's niece when a cop questions her. She realizes too late she doesn't even know what her alleged job is.
- Played for laughs in a FoxTrot strip; Paige tries to forge her fathers signature on an excuse note to get out of gym class, but her teacher catches on because the I's are dotted with little hearts.
- Knights of the Dinner Table:
- Brian's character gets into trouble attempting to enter a walled city during a Grunge Warrior game when he presents the guards with forged papers that identify him as an ambassador from a country that ceased to exist 30 years previously.
- Bob and Dave's characters disguise themselves as acolytes to sneak into a temple and steal a (supposedly) valuable relic. When a suspicious guard asks them basic questions of temple doctrine, Bob's response is "I tell him we've taken a vow of silence."
- The title character of Mulan does this when asked her name. Her family name (which she must use as part of the cover story) is Fa, but she hasn't thought of a personal name, leading to a very awkward conversation where Mushu tries to secretly help her come up with a name. One of his suggestions is Ah Chu, which would have lead to the cover identity being Fa Ah Chu.
- In Wreck-It Ralph, Ralph tries to pose as a candy cane tree inspector while quizzed by Vanellope, but she sees through this lie immediately because he clearly knows nothing about her game world.
- In The Jungle Book, Baloo disguises himself as an ape to have a ball at King Louie's party. However, Louie then smacks him on the back, causing his coverings to fall off.
- Played with in the movie Superbad, where Fogell gets a terrible fake ID that only has the name "McLovin". (The fact that there's no first name is bad enough, but the signature on the license clearly says McLoving.) It actually appears to fool the cops, and they end up going on an adventure with the kid. Subverted in the end, when they reveal that they immediately saw through the fake but wanted to have some fun and show him that not all cops are assholes.
- In Romy and Michele's High School Reunion they are pretending to be "successful businesswomen" to impress people. It is only when a waitress asks them what business they are in that they realise they may have neglected a vital element of their cover story. During a dream sequence, Michele actually supports her cover by rattling off a complex but plausible method of developing the adhesive for Post-It Notes, which they claim to have invented. Interestingly enough, it wasn't scripted - the actress improvised thanks to actually having an education in science.
- In Star Wars: A New Hope, Han and Luke are disguised as stormtroopers aboard the Death Star, to rescue Princess Leia, when they're forced into a shootout with some real stormtroopers. After killing them, Han rushes to a com unit to try and fool the troopers on the other line that nothing's wrong, and the following conversation takes place:
Han: [sounding official] Uh, everything's under control. Situation normal.
Voice: What happened?
Han: Uh, we had a slight weapons malfunction, but uh... everything's perfectly all right now. We're fine. We're all fine here now, thank you. How are you?
Voice: We're sending a squad up.
Han: Uh, uh... negative, negative. We had a reactor leak here now. Give us a few minutes to lock it down. Large leak, very dangerous.
Voice: Who is this? What's your operating number?
[Han shoots the intercom]
Han: [muttering] Boring conversation, anyway... [shouting] LUKE, WE'RE GONNA HAVE COMPANY!
- In the final sequence of Stalag 17, Sefton confronts Price, the Nazi double agent in the PoW barracks. Price stands up pretty well to questioning, until Sefton asks him when Pearl Harbor was bombed. He knows the right day and time, but forgets about the time difference. He gives the time in Germany, when it was about six hours earlier in the US.
- In Ace Ventura: Pet Detective, Lois Einhorn is revealed to be Ray Finkle when she yells in a man's voice at commentary of the "Kick Heard Round The World" that drove him over the edge.
- In To Be or Not to Be, the German spy gives himself away by not knowing who Maria Tura is, despite her being a hugely famous actress in his supposed hometown.
- In No Man of Her Own, Helen tries to convince her doctors that she isnt Patricia Harkness, but they think she's just confused because of the train crash she survived. The Harkness family then takes her in (never knowing what Patricia looked like). She decides to go along with it because shes penniless and has a newborn baby in tow, but she makes a lot a simple mistakes about the Harkness' son (Hugh) who Patricia was married to.
- Tinker, Tailor, Soldier, Spy. A Soviet military officer is seen saluting the cultural attache, despite the fact that he's a civilian with no war service. This causes the analyst who spots this to suspect that he's The Handler of a KGB mole, but her suspicions are not listened to and she's forceably retired.
- Inglourious Basterds has an example with disastrous results. In the tavern scene, Lt. Hicox seems to avoid this until he orders three Scotches using his index, middle and ring fingers — supposedly like a Brit — as opposed to his index, middle and thumb — like a German. This blows his cover and results in everyone in the bar except Hammersmark and a Heer grunt dying in a 15 second shootout.
- In Terminator 2: Judgment Day, after being rescued from the T-1000, John Connor orders the T-800 to stop next to a payphone, so he can warn his foster parents about the T-1000. Janell, his foster mother, answers the phone, and sounds incredibly worried wanting to know where John is so she can go pick him up and bring him safely home. John tells the T-800, that Janell has never sounded so nice or concerned. The T-800 asks John to give him the phone:
T-800: What's the dog's name?John: Max.T-800: (As John) Hey, Janell, I hear Wolfie barking, is he ok?Janelle: Wolfie is fine dear, just fine. (Sternly) Where are you?T-800 (Hangs up phone, in his normal voice) Your foster parents are dead.
- Skulduggery Pleasant. Scapegrace has a problem that causes him to invent a twin brother, of course he gets every detail right and thinks of everything.... except one of the names.
- Harry Potter:
- In Harry Potter and the Chamber of Secrets, Harry and Ron use Polyjuice Potion to pretend to be Crabbe and Goyle, but their infiltration of Slytherin House is stymied by the fact that they don't know how to get in to Slytherin's chambers. They ask a passing student, but she's from Ravenclaw. Fortunately, Crabbe and Goyle are so dim that they're not really acting out of character. They asked the Ravenclaw where the common room was, and were lead there by Draco. They had an Oh, Crap! moment when Draco asked them the password, but were saved when Draco remembered it before they did. Other instances of them being out of character for Crabbe and Goyle are when Harry didn't know what Azkaban was and when both of them forgot to laugh at a Daily Prophet article where Ron's dad gets in trouble with the Ministry.
- In the movie, Harry almost gives it away by still wearing his glasses. He quickly excuses them as reading glasses, causing Malfoy to stare at him skeptically and, courtesy of an adlib by Tom Felton, to remark that he didn't know "Goyle" knew how to read.
- The specific example of the location of the Slytherin common room comes up again in Harry Potter and the Deathly Hallows, when Scabior says people have claimed to be Slytherins when caught by his gang of Snatchers but couldn't say where the common room is. Because of his previous experience, Harry can actually answer this question which throws Scabior for a moment, but not enough to let Harry go.
- X-Wing Series: Face Loran, in disguise as Captain Darillian, stumbles into one of these when Admiral Trigit uses a catch phrase from Imperial Intelligence doctrine, which Face doesn't recognize but Darillian should know instinctively. The Alliance agents do come up with the explanation of the phrase for him (after a few seconds), but Trigit is still suspicious. Naturally, Face bluffs his way out of it, first by seemingly confessing the truth ("I'm not the Zurel Darillian you knew"), then by distracting Trigit with a tale of having been in love with Ysanne Isard. Or, more specifically, of having an unrequited crush on Ysanne Isard, bringing out a TON of background info to overwhelm Trigit, AND finally bringing up a detail only someone who met Ysanne Isard would know. Namely, the specific perfume she wears, which Face knew because he met her once, and only once. The ship applauds.
- A Song of Ice and Fire. While on her quest to find the fugitive Sansa Stark, Brienne of Tarth claims she's looking for her sister, but forgets to think up a false name for her. It's a moot point anyway, as most people can tell who she's looking for just from the description, given that she's rather high-profile (when the heir to the North is a suspect in the murder of the King, word gets around) and there's a lot of other people searching for her.
- On Wings of Eagles by Ken Follett. 'Bull' Simons insists that the EDS men he's taking out of Iran learn the details on their fake passports off by heart. Everyone thinks this is an unnecessary precaution until just before they reach the border, when they're stopped at a guerilla checkpoint and grilled on these exact details.
- Several of these in The Spycatcher's Omnibus by Lt. Colonel Oreste Pinto. In one case, Pinto is alarmed to discover a high-ranking British official who is a notorious ladies man has got himself a new Sexy Secretary, a refugee from German-occupied France who did not pass through the routine security clearance. He has to do an ad-hoc interrogation there and then, with the official constantly demanding Pinto hurry up (despite the fact that such interrogations normally take days). Pinto suddenly has the idea of telling the woman to take off her shoes, which reveals her nice soft feet — despite her claiming to have walked all the way from France over the mountains to Spain. The official is flabbergasted when Pinto informs him his secretary has just confessed to being a German agent.
- The Tommy and Tuppence novel N or M?
- Tuppence is undercover as an "unofficial" agent at a seaside inn attempting to root out a German spy. She has made up her own elaborate back story where she has three sons, one serving in each branch of the military, who send her letters in secret code. At one point, she talks about her "own two", momentarily confusing her real-life twins with the made-up sons. When called on it by the inn's owner, she covers it by explaining that two of her sons were very close in age and spent more time together than with the third sibling.
- Tommy, undercover at the same time, averts this; his background was made up by the intelligence agency he's working for to fit in neatly with his existing life and not be too elaborate to remember.
- The Executioner. Inverted in "Brothers in Blood", where a woman tells Bolan about a group of 'hunters' (actually a hit squad hunting Bolan) "dressed up in denims and huntin' caps and hikin' boots and so forth — nothing wrong with them, and that was what was wrong. They looked like they'd stepped out of an L.L.Bean catalog, outfitted up and ready to go. I say to myself, Miss Jane, here is a mess of folks trying to look like something they ain't."
- Nick Velvet: In "The Theft of Nick Velvet", the killer accidentally exposes himself while claiming to be an artist from Johannesburg and talking about the excellent southern light in his studio. As Nick points out, in the southern hemisphere, artist's want northern light.
- Flashman and the Great Game. Flashman is posing as a recruit for a native cavalry unit in India. Despite claiming that he has no previous military experience, the Old Soldier quickly spots him as a fraud because Flashman is unconsciously standing the correct distance from his desk, and has bridled his pony in the regulation manner. Fortunately this serves as an Infraction Distraction as everyone assumes he's just on the run from a tribal blood feud, rather than a British officer in disguise.
- When Flashman is posing as a British naval officer in the United States, someone later points out several dinner habits a navy man would have that Flashman failed to emulate (being an army officer).
- In the Being Human (UK) episode "The War Child", Eve is being smuggled into a concentration camp by a freedom fighter claiming to be her father. Unfortunately, Mr. Snow tests this story by asking the man what colour Eve's eyes are. He doesn't know.
- Burn Notice:
- Came up as early as the second episode. Mike is impersonating a friend of a friend of the Villain of the Week, Quentin King. Quentin slips a Bluff the Impostor into an offhand remark about their mutual cellmate Paco. The Department of Corrections file Mike used as a source for his cover ID didn't say whether Paco drank, so Mike guesses that he didn't. He was rightnote . As soon as his mark turns away, Mike lets out a grossly exaggerated "whew" face.
- In later episodes, he gives examples of what to do if the Cover Identity Anomaly slips during a Bluff the Impostor moment: keep lying* . In a similar case to the above, he's asked a question and gives the wrong answer (it's another drinking question, and he says that the friend of a friend never drank). When the target calls him on it, Mike simply says that the friend of a friend gave up drinking in prison and found religion, which the target thinks about and accepts.
- In the pilot episode of Cheers, Sam isn't fooled by a teenager's fake ID, because it not only claims he's over forty, it's a falsified military ID.
- Death in Paradise: In "Death of a Detective", a woman has assumed the identity of her sister. However, she had never read the novel on which her sister did her dissertation at Cambridge.
- One episode of Degrassi Junior High has Snake trying to get alcohol for a party. It would all be well and good except for the fact that the fake ID doesn't even have a picture on it.
- Doctor Who: In "Nightmare of Eden", the Fourth Doctor claims to Captain Rigg that he's an agent of Galactic Salvage Insurance, only for the captain to point out Galactic Salvage has been out of business for twenty years. Being the Doctor, he makes a brazen attempt to keep the bluff going:
The Doctor: I wondered why I hadn't been paid.
Rigg: That's not good enough.
The Doctor: That's what I said!
- Subverted in the Farscape episode "Losing Time". The crew are informed that an "energy rider" had invaded the body of one of them and that they can find out who it is since the rider won't know "details of the heart" like family members. They get misdirected when a new member of the crew tells a different story about her background than the one she initially told them and they assume she's lying. In truth she'd been lying the first time.
- Game of Thrones. Brienne is escorting Jaime Lannister back to King's Landing when three Northern soldiers recognise him as the notorious Kingslayer. Naturally they deny it, with Brienne claiming Jaime is a thief she is taking to Riverrun to be thrown in the dungeons.
- Narrowly averted in the pilot. Mike has to go undercover as the brother-in-law of a low level drug dealer in order to prevent Russian mobsters from killing the dealer's family. The brother-in-law is a real person with a criminal record that the Russians are aware of. Mike only vaguely matches the man's description and is shorter and thinner than him. They compensate by having him wear platform shoes and blaming the weight loss on drug use. Mike still almost gets caught when he has to tell the Russians about a murder he claims to have committed and the FBI agents listening in on the conversation from Mission Control have to quickly create a fake crime report that matches what Mike said and insert it into the relevant police databases.
- In another episode Mike pre-empts this when he pretends to be a Marine selling stolen military weapons. Almost immediately after selling the weapons to a gang, the gang gets hijacked by another gang which takes those weapons. When the angry gang leader suspects a setup and questions Mike about his whereabouts during this hijack, Mike angrily tells them that he was on base and they can easily verify it by checking with his duty sergeant. The sergeant does not exist but Mike knows that, unlike the Russian mobsters, these gang bangers do not have the contacts to verify his story or even confirm that someone with that name is even enlisted in the Marine Corps.
- Motive: In "The Vanishing Policeman", the murderer is posing as a police officer in order to stage a fake suicide. However, in watching video of the 'suicide', Angie notices that he was wearing his baton on his right side. Angie knew that the officer in question had been wounded the week before and, as the baton rubbed against his stitches, he had moved it from the right hand side of his belt to the left.
- This almost gets Callen killed in an episode of NCIS: Los Angeles. The team intercepts the communications of a terrorist cell and realize that the terrorists are expecting a new member to arrive whom they have apparently never met before. They arrest the terrorist and Callen takes his place. However, the cell's leader actually went to school with the man Callen is impersonating. They were very young at the time and never became friends so Callen is able to bluff his way through the questions he is asked. However, he trips himself up because in their hurry to make the switch, the team failed to realize that the new terrorist is left-handed. The cell leader clearly remembered this about his former schoolmate and when he sees Callen write using his right hand, he knows that they are being tricked.
- Person of Interest
- An executive at a computer security company tries to send flowers to the parents of an employee killed in a traffic accident. When it turns out that the parents do not exist, she quickly realizes that the man was a Chinese spy. She also realizes that someone high up in the company must have been working with the spy or this would have come up on a routine background check. It turns out that many of the company's employees, including most of the executives, were Chinese spies.
- The Machine has Root and Shaw infiltrate a CIA black site by having them pretend that Shaw is a CIA agent delivering Root as a prisoner. The Machine is unable to obtain all the correct security codes so Shaw has to say that she was in a hurry and forgot to get the new codes. The suspicious guard is about to radio in to his superiors for verification of her identity but his radio malfunctions. Shaw is able to tell him the correct procedure for resetting the radio. The procedure was designed specifically to prevent unauthorized personnel from using the black site's equipment so the guard accepts this as proof that Shaw really is part of the unit.
- Reese is captured along with three other Badass in a Nice Suit mercenaries in "Prisoner's Dilemma". All have impeccable cover identities, but FBI agent Donnelly is convinced one is the Man in the Suit vigilante, so it becomes a race to maintain Reese's cover until one of the mercenaries' cracks.
- In Season 4, Reese has a cover identity as a police detective. While working as a tactical instructor, a female trainee notes that he uses military tactics despite his file not showing the appropriate background. Reese fudges the issue by claiming he was taught by an instructor who was a Gulf War veteran.
- The Saint: In "The Organisation Man", Templar, working undercover for British military intelligence, has infiltrated a small private army whose current assignment is to liberate a captured, high-profile spy. They're disguised in the stolen tartans of a detachment of Scottish soldiers who were due to take over guard duty, and on handover, are being inspected by the current guard commander. Their disguises are perfect (as befits a regiment known for their punctilious attention to detail), up until the point when the commander notices that they've all placed their sgian-dubh knives in the wrong sock - the right rather than the left.
- The British comedy series Spaced features Tim and Daisy, who are pretending to be a couple in order to rent an apartment. Though they attempt to be as thorough as possible by learning a multitude of mundane details about each other ("I forgot what you got for your fifth birthday!" "Miniature drum kit"), they get caught in their lie while fumbling around regarding what day they had sex first vs. what day they kissed first.
- A much worse mistake is barely averted as, just before they go in, they realize they've never learned each other's names.
- Star Trek: The Next Generation: In 'Future Imperfect', a boy posing as Riker's son misses a vital piece of information about the woman he claims is his mother - she only ever existed as a hologram.
- On Turn an American agent is trying to infiltrate British-occupied New York by posing as British officer who was captured by the Americans and is being exchanged in a prisoner swap. The agent is quickly discovered when he does not know his regiment's motto and later makes a few more mistakes including failing basic European dinner etiquette by holding his fork in his left hand.
- An episode of Veronica Mars deals with Veronica's dad, who has been temporarily reinstated as sheriff, cracking down on bars that serve alcohol to minors despite the obviously fake IDs. The only two teens whose IDs are very good Sheriff Mars happens to know personally, and he also happens to know that they were laminated using his own ID card printer. He then has his deputies conduct random ID checks at bars. When that doesn't yield results, he sets up the same two teens with obvious fakes (with pictures of Jon Bon Jovi and Biggie Smalls) and has them drinking non-alcoholic beer at a bar about to be inspected by one of his deputies. When the deputy doesn't attempt to arrest the two teens despite the obvious fakes, the sheriff has him and three others fired.
- Paul Temple and his wife Steve, in addition to revealing impostors by using a question or comment, have a couple of occasions where an impostor simply gets one detail wrong.
- In Paul Temple and the Alex Affair, Temple gets a phone call from his friend Leo Brent, whom he has sent to stake out a hotel. The caller is a plausible impostor, but his error is addressing Temple several times as 'Paul', when, as Temple remarks to Steve, Brent always calls him 'Temple'.
- In one episode, Steve receives a phone call from another very plausible impostor claiming to be her husband. The only way she knows it isn't him is because he uses the expression "By George!" rather than his usual "By Timothy!"
- This is a suggested possibility for Shadowrun characters whose false identities fail security scans. On a critical glitch, a suggestion is that some part of the data is clearly false (e.g. an elf's SIN identifies him as a female troll).
- This entire trope is a game mechanic in Demon: The Descent. Long story short: The Player Characters are the titular demons and can create pacts with motals, which trades some part of the mortals life (fiancee, house, university education etc) for money, power, love, any of the usual stuff really. The reason Demons do this is so they can integrate whatever the mortal traded away onto their own supernatural disguises to make them more "real", but the catch is only things directly involved in the deal get changed. So the Demon might gain the true love and affection of someones fiancee, but all of their family will remember them being engaged to a completely different person, or you might gain a diploma with all the paperwork to match, but none of the university lecturer's or anyone in the graduating year will remember them. When these discrepancies start getting noticed they start to wear away at the Demon's disguise, which leaves them vulnerable to being noticed by other supernatural creatures, or worse, the God Machine.
- One mission in MechAssault has the player pilot a captured enemy Thor into a Word of Blake base to download some intel from their computers. The disguise almost works, until one of the Blake officers asks you to transmit your ID code or be fired upon. Fortunately, they wait just long enough for Foster to download the intel.
- In Tales of Symphonia: Dawn of the New World: Emil Castagnier. Being the summon spirit Ratatosk in human form, Emil lacks a lot of information that would be expected from a resident of Palmacosta - fishing, the Desian Human Ranch nearby, etc. Subverted in that he is unaware of what he is Beneath the Mask for most of the game
- In a mission in Hitman 2: Silent Assassin, Agent 47 can adopt a disguise of a "Lord Sinclair" to get close to his target (a female doctor). If she asks 47 for the name of "his" wife, though, he won't know what to say before eventually randomly coming up with "Elsie" (which is way off the mark), blowing his cover.
- Subverted in the 2016 Hitman, where in the Bangkok level 47 can disguise himself as a drummer of his target's band. If he's asked to show off his skills, 47 plays a decent beat and his disguise remains intact.
- In Saints Row: The Third, the Boss disguises himself as Cyrus Temple, the leader of S.T.A.G., to infiltrate their base and save Shaundi. While Magic Plastic Surgery means the looks and voice are perfect, the Boss makes little to no attempt to try and speak like Cyrus. Depending on your chosen voice and gender, this can result in "Cyrus" doing things like hitting on his subordinate, talking about how cute a guy is, or speaking in various accents.
Kia: Welcome back, sir.Cyrus!Boss: Whassup?
- Renard Vulpes in Aviary Attorney goes by Juan Querido, prince of Spain. Problem is that's actually pretty easy to check — there are no significant princes of Spain and "Querido" is probably not a real name. However, only his defense attorneys bother to look that up. Despite him being charged for murder and attempted murder of the king of France.
- Papers, Please: Spotting these is the core gameplay element of the game.
- In Fallout 2, if you buy the forged citizenship papers for Vault City, the first time you go through the security checkpoint they take an awfully long time scanning them but as long as you keep your cool they'll let you through. If you panic, you'll get caught.
- In Phoenix Wright: Ace Attorney - Trials and Tribulations, an impersonator doesn't know that the person he's imitating recently suffered an injury that made him unable to hear out of his left ear. When a witness who was fooled by the imitation testifies that the person was wearing an earpiece in his left ear, Phoenix has to point out that it makes no sense.
- In League of Super Redundant Heroes, an alien named Zoolkor Lizard-Face Humankiller has what seems to be the perfect disguise for infiltrating human society, but the name she uses as such, well, needs work.
- In Survivor: Fan Characters, Bonnie returns in one season disguised as "Sarah", a seemingly sweet therapist for "Bonnie" who's actually an actress hired to impersonate her. She invents a sob story as Sarah about a dead mother, which comes back to bite her in the rear end when she's unable to tell Brandi the name of her supposed dead mother.
- Meanwhile, on Not Always Right, a youngster trying to buy cigarettes is using her older sister's ID, so she looks like the photo and knows all the facts... but the shop clerk went to high school with said sister.
Bouncer: Is this your ID?Guest: Yep.Bouncer: *Turns to guest's friend* What's her name?Friend: Uhhhhh....
- The same source had a bouncer ask a guest:
- Avatar: The Last Airbender has Sokka trying to pass himself and his sister Katara off as Aang's parents when he gets in trouble with his teacher at a Fire Nation schoolnote , leading to the hilariously badass Paper-Thin Disguise identify of Fire. WANG Fire!. And his wife, Sapphire Fire. As with many examples of Refuge in Audacity on the show, this works beyond any reasonable expectation because it's funny.
- This has happened many times to Bugs Bunny, usually with his ears or tail sticking out from his disguise.
- This has also happened, most likely as a Shout-Out to the above, in the Tiny Toon Adventures episode "The Looney Beginning" when Montana Max sees Buster and Babs' tails poking out of their outfits.
- In the My Little Pony: Friendship Is Magic episode "Spike At Your Service", the main characters stage a fake Timberwolf attack for Spike to rescue Applejack from, and Spike is fooled at first, until he notices that the fake Timberwolf doesn't have bad breath.
- The Simpsons:
- In "Blood Feud", Homer attempts to pretend he's Mr. Burns... except he doesn't know what Mr. Burns's first name is.note
- In the "Treehouse of Horror X" story "Life's A Glitch, Then You Die", when Homer pretended to be the pianist from the movie Shine. When asked for his name, he responds "Shiny McShine".
- In "Lard of the Dance", when attempting to steal Springfield Elementary's grease, Homer and Bart are confronted by Groundskeeper Willy. When Willy demands to know what is going on, Homer claims to be a foreign exchange student from Scotland. When Willy presses him for where in Scotland, Homer hesitantly states "North... Kiltown?" When Willy says that he's from North Kilttown and asks if he knows Angus McLeod, Homer inverts the situation, stating there is no Angus McLeod in North Kiltown and it is Willy falsifying his identity.
- Star Wars Resistance: Although Kazuda Xiono uses his real name when he's sent on a spying mission to the Colossus refuelling station, his cover is that he's a mechanic and aspiring pilot. He's fine at the piloting part of it, since he used to be an X-Wing pilot in the New Republic Navy, but the mechanical end not so much. Since he spends more time at his mechanic job than flying in the races held at the station, this causes him some trouble, and makes his Locked Out of the Loop co-worker Tam Ryvora very suspicious. However, over time, Kaz's mechanical skills improve somewhat.
- This is the point of "Security Questions" on websites when you need to reset your password; they're intended to foil someone pretending to be you, by asking questions that only you should know the answer to. Some places invert this and actually advise you to put something that is completely wrong (but that nobody would guess) as the answer, for example if the question is "What is your birthday?" put "Puppy", so that if the pretender does find out your info they can't get into your accounts. (This assumes, of course, that the system will accept such an answer to that particular question; for a system that accepts only dates for a "birthday" question, one can still enter a wrong date.)
- Standard tradecraft for spies when communicating is, to give a hint to their controllers if someone was faking their communications, to have a subtle challenge code that, assuming the spy hadn't gone full Double Agent, would be something the faker wouldn't be able to respond correctly to or even realize they were expected to respond to. The same principle was used for dead-drops: often a legitimate drop required some subtle thing at another location to verify the drop.
- One quick check used in stores to challenge customers who appear too young for the purchase (typically alcohol and/or cigarettes) and might have a fake ID is to ask what year they were born. Someone faking their age is likely to trip up and give their actual birth year or obviously have to stop and think about what year they would have had to have been born to be legal.
- A similar practice works (less reliably) for signature forgers. While the person is signing their name, if they're asked a question that they have to stop and think about, they're more likely to mess up their signature if they're not used to writing it.
- An OSS training film on undercover operations notes the importance of even minor details conforming to an agent's cover story, from clothing appropriate to a person of the agent's supposed means, a haircut that conforms to local trends, all the way down to the presence or absence of callouses on the hands of a laborer vs. an office worker. One section (https://www.youtube.com/watch?v=1eZ9p7s43WM) even tells the stories of three agents whose covers were blown by seemingly innocuous details - one who tried to pay for a drink with out-of-date currency, another who didn't pick up on local slang despite supposedly being a local, and a third who was caught wearing hair gel that he could only have purchased in an enemy country. (The complete film is viewable here: https://www.youtube.com/watch?v=v4F6aqo3Yp8)