It's sometimes fun to actually see how someone gets past what should have been rock-solid security. Some people go for a version of the Foe-Tossing Charge. But then, in the manga of Slayers, a five-story building has been filled with warriors and magic-users fully capable of matching Lina in a fight. As the villainess gloats about her tight security, Lina walks in. She just used a flying spell to float up to the top floor.
Mokuba: But I thought I sealed all the exits? Oooh, I hate continuity...
You know, maybe trusting Mokuba with things like that isn't always a good idea...
In the first episode of Naruto, Naruto, a 12 year old boy who had just failed (for the third time!) to become a genin, manages to break in to the Hokage's office and steal a scroll containing forbidden ninja techniques. Lampshaded in Naruto The Abridged Series when the Hokage yells at a crowd of ninjas about it.
Earlier in that episode he was running away from defacing Hokage Mountain. Keep in mind that you can see it from just about every point in the village. Naruto is apparently a sneakier ninja than we thought.
That's the point. Naruto is Book Dumb, but he does have some skill.
In the manga, the ninja find him painting the monument instead of escaping from doing so, and he gets caught by the Third Hokage, but escapes by using the Sexy Jutsu.
Chapter 482 of Bleach: somehow seven masked men are able to boldly walk into Captain-Commander Yamamoto's office to deliver their declaration of war against Soul Society. Even getting past the front gate has in the past been shown to be very difficult and doing so unnoticed should be impossible, as seen by the commotion the heroes caused when they broke in an earlier arc. Yet these guys aren't noticed until they walk through Yamamoto's door.
This turned out to be justified, as their base is in the same spot as the Soul Society, but in a different dimension, meaning all they had to do was switch planes to Soul Society and be there, as they're shown doing later.
The first time this happens, Motoko walks right into the front door of the mansion of a reclusive billionaire. The android maid-guard asks who she is. She just casually flashes her police badge, letting her get a good look at it, while saying that she's from a maintenance company and that it was time for a scheduled tune-up. The maid just stands back and lets her pass. When a Tachikoma walks in a few moments later, the maid asks who he is. He just responds that he's a Tachikoma and continues right on in.
This is also the method that the Laughing Man uses. He just flat out hacks everyone in the area so that they just plain don't see or hear him walking around.
In the first issue of Mega Man, Dr. Wily managed to sneak into Dr. Light's lab and reprogram the Robot Masters quite easily. This could be justified since the two were friends at the time, but Light never even knows they were there until the next morning.
It doesn't get played up much in The Movie but in the original comic version of Sin City, Cardinal Roark lives in a parish protected by elite federal agents. It is so heavily fortified, it has earned the nickname "Fortress Roark". Marv goes into great detail about how dangerous the place is... just before killing several guards with his barehands and waltzing into Cardinal Roark's bedroom.
While Smallville Lex Luthor's mansion security is practically non-existent, almost all comic book versions of Luthor are at least somewhat competent when it comes to security. Indeed, during the "Y2K" storyline (where Brainiac 13 seriously upgraded the city of Metropolis' tech level), Luthor's new, truly ridiculous security measures kicked Superman's ass.
Subverted in Ultimate Spider-Man, when Spidey tries to intimidate the Kingpin by dropping in on him unexpectedly, only to realize that the Kingpin put in shatter-proof windows to get rid of such problems. Makes the web head lose his cool. Kingpin doesn't even blink at the sound of Spidey hitting his window.
The Rich Mansion (as in, where Richie Rich lives) is an odd case. The place naturally attracts lots of thieves (Richie's family stores at least a portion of their assets in vaults built inside the house itself; either his parents don't entirely trust banks, or they have more material wealth than they can store in them, which might actually make sense.) While it seems easy for crooks to break into an rob the place, they tend to be caught later rather easily; so while the place has yet to be the target of a perfect crime, it does seem like, at least, the perfect target.
Averted when Iron Man tried infiltrating Doctor Doom's castle with an armor that can become invisible. When he tried, Stark forgot the little fact that Doom's had enough run ins with the Fantastic Four's Invisible Woman sneaking around to have numerous sensors everywhere specifically designed to detect invisible intruders.
One issue of Catwoman's own title seemed to mock this Trope. After effortlessly stealing a priceless statuette from a museum, she was rather disgusted at how incredibly easy it was, so she returned it to the museum with a note telling them how crappy their security was. They proceeded to upgrade the security... Then she stole it again, then returned it again, then stole it again, repeating the process at least a dozen times over the issue, even as the curator kept putting heavier security on the place. (Maybe she wanted to prove how good she was, or she simply had too much free time.) Eventually, the curator was considering letting her keep it - figuring he'd get more from insurance than the cost of protecting it - but she thought this was getting boring, and returned it to him in person, told him that his museum sucked, but left saying she'd keep an eye on the place. (As in, to keep him on edge.)
In A Frog In Arkham Asylum, Jade actually uses the words "swiss cheese" when describing Arkham Asylum to Hugo Strange. In fact, she claims that the only reason she hasn't escaped yet is that she was framed and wishes to clear her name, and trying to escape would make her look even more guilty. Strange even mentions several chances she DIDN'T take (and it should be noted that there are likely more occasions he doesn't know about).
In Star Trek Into Darkness, Harrison is able to massacre much of the Starfleet High Command simply by flying a ship up to their meeting room and blasting them, totally uncontested. If Kirk hadn't disabled his ship, forcing an alternate escape, he probably could have flow right back out when he was finished. Later on, Scotty is able to board the super-secret Vengeance by simply flying his shuttle into its hidden spacedock, which apparently has no sensors to detect incoming ships.
In Alien: Resurrection, Ellen Ripley and the rest of the cast, without any keys, identification cards, or anything else of that sort, effortlessly navigate around a very important military-scientific complex housed inside a government owned spaceship, even going into a room with top secret Ellen Ripley clones just by pushing the door open. Granted, they had a scientist with them who might have known a few access codes, and Call was also a robot who could hack into the spaceship's computer to open all the doors, but the scientist wasn't shown opening any doors, and Call only hacked into the ship's computer and opened all the doors toward the end of the movie.
Avatar almost gets away with the inverse of this: The only thing that tips Quaritch off to Jake and co's jailbreak is a gunship telling the base what it's doing, despite Jake's wheelchair.
The Avengers (1998). The meeting of the Council of Minsters (a group of high government officials) apparently has no security whatsoever. Sir August and his color guard are able to walk right in without opposition, and walk out again unopposed after making extortion threats.
In Daredevil, the Kingpin is surprised that Bullseye broke into his corporate office. When Kingpin asked how Bullseye got past his security, Bullseye pointed to a guard he just killed. Bullseye even admitted that killing the guard wasn't necessary, but funny.
Independence Day: Driving an RV convoy into Area 51? On one guard's word? Go right ahead. And no one seemed to even see them until they were in visual range.
Invasion of the Neptune Men features the Earth under attack from a group of aliens. The world is on high alert, scientists are working around the clock for ways to combat them...and a group of children can seemingly walk right into any military building without question. The MST3K episode lampshades this: "Apparently the kids have level five security clearance."
Mars Attacks!. The Martians are able to walk into the underground facility where the President of the United States is hiding after their attack. Not only are they not stopped, the Secret Service team doesn't even know they're coming until they appear.
In Minority Report, Tom Cruise's character goes on the lam, but manages to get back into the most secure portion of headquarters, using his own retinal scan. When he's arrested and detained, his wife uses his retinal scan AGAIN to break him out of containment.
In Serving Sara, the main character needs to get into a building with a security guard at a desk in the lobby. Admittedly, this isn't exactly airtight security, but his method of distraction is worth this entry. The character is looking at a tow truck whose driver is changing a flat tire. Cut to the lobby of the building, and a flaming tire rolls right past the guard.
In Terminator 3: Rise of the Machines, it was never shown how the T-850, John and Katherine managed to get through a secret military base all the way to the well-guarded control room from where Skynet was launched. The novelization, however, did a Hand Wave.
In Beverly Hills Cop, Axel Foley gets into a Federal Customs facility merely by hopping a fence, then flashing his badge to the first person he sees and ordering everyone around. They assume that, if he's inside the perimeter, he must belong inside the perimeter.
Subverted in Anne McCaffrey's The Rowan. After the main character gets over their fear of travel she plans to pay a surprise visit to her boss, teleporting into his office. When her second in command tells the boss he arranges to switch off the security that would otherwise fry her the second she arrived (she's not the only teleporter).
In one of Kirk Mitchell's mysteries starring FBI agent Emmett Parker, Parker is accused of murder, being hunted by the FBI, and he manages to get into their Oklahoma headquarters. The only explanation given is that it's very early in the morning, well before office hours start. He even talks to an agent there and then escapes (the agent gets into trouble).
Played with in the second Deltora Quest series. The Shadowlands are a huge Mordor-like realm filled with the Shadow Lords servants, its borders however are completely and totally unguarded. The heroes mention out loud that it's not quite what they were expecting. They figure it out when a small lizard runs across the border but hits an invisible wall on the way back. Turns out the Shadow Lord is quite happy for people to get in, they just can't get out afterwards.
In The Dresden Files, Marcone doesn't even bother with security against Harry Dresden (mostly...). All businesses he owns are instructed to give Dresden the VIP treatment, and escort him inside immediately with special discounts and lifetime memberships. He also knows that a sufficiently motivated Dresden can pretty much destroy any nonmagical barrier placed in his way, so at his actual hideouts he makes sure that the walls are crazy reinforced, while the most dramatically appropriate doors are designed to explode into as few dangerous fragments as possible.
In Gaunt's Ghosts, in order to prove that only the Tanith are capable of protecting Mabbon, Rawne pretends to be an assassin and easily thwarts his bodyguards and breaks into his cell. Not only that, but actual assassins also happen to break in at the exact same time.
Bernie, in Lawrence Block's Burglar series, comments on how his uncle lifted a sign by pretending to be maintenence. Bernie himself often uses the clipboard routine.
Gregory McDonald uses a variety of methods to get Fletch in where he needs to be, and Fletch and Flynn discuss Flynn's methods of spying as a child in Nazi Germany.
For all that Merlin's Camelot is meant to be impenetrable it is invaded constantly; even in the first episode. Merlin himself is able to go anywhere he wants.
It gets even worse in the fourth season. You know it's really bad when the villain says: "taking the castle was the easy part".
Angel regularly lampshades how easily intruders can get into Wolfram & Hart without (immediate) notice. Indeed, after abusing this lax security for years when Wolfram & Hart was the opposition, Angel then discovered that their security didn't improve much even after he and his friends were put in charge of the W&H LA branch office.
Angel: Call security, put 'em on red alert. Nobody gets in this building without clearance from me. I want a guard at every entrance, every elevator, every stairwell. Cover the whole building.
Frequently featured and lampshaded, often attributed to the villain's inability to find competent minions for security.
Spike: Do we have any security around here? Or have we finally found a restaurant that delivers...?
Nobody in Sunnydale ever locks any doors.
The Farscape three-parter "Look at the Princess" is full of this. Despite endless comments about how tight the security is in the lead-up to the Royal wedding, the various protagonists and antagonists have no problem carrying out various kidnappings, assaults and assassination attempts on each other.
Partially justified since the members of the royal family were in on some of the kidnappings and assassination attempts to begin with.
Nip/Tuck season 5 is a major offender especially because the series is quite level headed and grounded in (to a point) reality. Colleen harassed Sean throughout half of the season, and in this time (from the point she is discovered to be an impostor) she managed to break into: the studio Sean was working in, his apartment to try to kill herself and die in his arms, his clinic (although it does have a flimsy security at best) in order to beg that he fixes her pulse, the Studio AGAIN, and this time presumably knocking out another minor cast member of the series he was part of since she took the role of an assisting medic within and in dangerous proximity to a blade, his apartment AGAIN to plant a BODY of a "rival" agent (she wasn't a real agent to begin with), and finally at his clinic AGAIN to try and murder him. That's made worse by the fact that she is an ordinary (albeit crazy) middle-aged woman. Not only does she break into 3 locations that ought to have some sort of security, she does so again in the SAME ORDER with apparently no difficulty whatsoever.
In the 2006 series of Robin Hood, the Merry Men seem able to waltz into Nottingham Castle any time they feel like it.
When Alan A Dale does one of his Face Heel Turns, he shows the Sheriff and Guy the passageways they use to get in. The Sheriff has them closed off. A few episodes later, this is forgotten.
Seinfeld has an inversion: Jerry would not let one of his own neighbors into his apartment building.
In the Stargate SG-1 episode "Shades of Grey", Jack O'Neill (who has been forced to resign from the Air Force in order to avoid criminal prosecution) is able to waltz into Stargate Command and straight into General Hammond's office, without security apparently noticing his presence at all. Now, he is a former Black Ops veteran and ex-second-in-command of the base, but it still stretches the bounds of plausibility quite a bit. In fact, all secret bases in Stargate SG-1 seem to have Swiss Cheese Security, from Goa'uld strongholds to the SGC to NID prisons.
The incident in "Shades of Grey" is actually more or less justified, as the entire thing was a Gambit Roulette organized by Hammond and O'Neill, and the latter may have been secretly given means to bypass security and slip into Hammond's office undetected. Besides, O'Neill never actually resigned his commission.
In the episode Prometheus, Major Carter and Quinn Escort a news crew into a top secret prototype spaceship without checking their equipment for weapons (They even had a Zat!) and with only two guards as escorts.
The psychic paper helps too, although not against places that are actually prepared for that.
It also doesn't hurt that the Sonic Screwdriver can open any lock, and disable pretty much any other security device, or that the Tardis isn't exactly inhibited by walls.
This comes up in the first episode of season 6, where the TARDIS landed in the Oval Office.
Canton: Mr. President, that man just walked in here with three of his friends and a great big blue box... [points at the Secret Service head] and that is the man he walked past. One of them is worth listening to.
In Mutant X, seemingly every time Mutant X wanted into Genomex (the Big Bad), they waltzed right in with basically nothing to stop them. Unless the plot called for one of them to get captured, of course.
It's partially justified since one of their members does have the ability to phase through walls and the Sixth Ranger who joins in the third season has invisibility as her main power.
The number of times people have managed to invade, hack, or subvert the Andromeda Ascendant is more than a little disconcerting. It can be hand waved a bit with the fact that the ship normally has a crew of thousands instead of 6 and that the people on board haven't had enough training to properly run it, but still.
The same thing happened to the Enterprise on TNG a LOT. One episode of DS9 even had Odo tease Worf about it. Seriously, in TNG only the bad guys ever enacted IT security pertaining to anything except the self-destruct. Forget circuit breakers, surge suppressors, seat belts, where were the PASSWORDS?
Deep Space Nine has nothing to brag about. The turbolift is apparently unrestricted, very often people who shouldn't be allowed in Ops unescorted (like Quark) stroll right in. Then again, Quark has proven he has security chips granting him security clearance even higher than Odo. He's just that good. In addition, Ops isn't so much a bridge like on the Enterprise as it is the manager's office (technically, a combination of the two). People are supposed to come up there with grievances and such (especially Quark, who is head of the station's business union).
Voyager had perhaps the worst security in the history of Starfleet, considering how often enemies were able to steal shuttles or hack their computer. One episode ended with two unarmed Ferengi overpowering their guards, getting to the shuttlebay, stealing their own ship, and escape through a wormhole.
In Prison Break one of the characters finds the President's brother in a house in the middle of nowhere. After going to a lot of trouble to fake his death, he doesn't even bother to lock the doors of his safehouse and Robin Tunney's character just walks straight in. Though they try to excuse this in the next episode by revealing that once in, nobody can open the doors out again. Though surely it would have been easier to just lock the doors from the inside.
Actually, you want people to fall into the trap, just to make sure no one outside finds out what happened. And any cell phone calls are intercepted.
The titular building of Dollhouse was originally impossible to find, let alone break into or escape from, until the end of the first season. After that, characters seem to be able to get in and out whenever the plot demands it.
Subverted in Burn Notice whenever Michael needs to get somewhere. They almost always show (or at least reference) how Michael gets to where he needs to be and it's usually acting like he's supposed to be there.
One Season Two episode has him walk into a government contractor with a friend claiming he lost his security badge. After he's inside, he further 'sneaks' into the high security area... by taking a soda can out of the trash and lifting a handprint.
A later episode has Michael again trying to get into a government building in order to obtain something. He walks in pretending to be the weekend cleaning crew. However, getting what he needs requires him to trigger an alarm. How does he get out? He allows himself to get caught by security, pretends he's drunk (and cuts himself on the window he had to break), and begs security not to report it since he really needs the job or his wife will take away the kids. Security pities him, reports a false alarm, and escorts him to the front door while suggesting he take the rest of the day off to get clean & sober.
Another episode has Michael once again triggering an alarm while already having gotten what he wanted inside a high-security building (specifically, a Police building). He slips on a Police jacket and starts yelling at people to find the intruder. It's specifically mentioned that new recruits are trained to follow higher ups' orders without question, so all he had to do was act like one.
Essentially, the show takes great lengths to avert this with the point it always makes being that getting somewhere is generally very easy. Ultimately, all security has some sort of weak spot whether it's a keycard, a person, or what not. It's getting into the right position to enter or leave without anyone thinking you're not supposed to be there that poses the problem.
Most of the big mansions in Port Charles of General Hospital have this type of security. It gets ridiculous with Greystone Manor, the home of mob kingpin Sonny Corinthos. That many people who want to kill him, and pretty much anyone who wants to can just waltz onto the premises?
White Collar has Neal walk into a bank dressed as a maintenance guy, insert fake credentials for himself into their mail system, change into a suit and walk up to a bank employee and pretend to be a freshly hired new accounts manager. The employee finds the 'new employee' package he planted and assumes that HR simply failed to call ahead. When his security badge fails to work, she uses her own since new badges tend to glitch out. With access to the inner offices, Neal easily swipes a real badge, walks into the vault, packs his briefcase full of cash and then walks out. However, this is a security test orchestrated by the FBI and Peter later shows the money to a conference room full of bank managers to prove to them how lousy their bank security is.
He also pretends to be a sportscar salesman to get into the dealership's computer system, and actually makes a sale. The implication is that he could've a)stolen a car b)gotten lots of people's banking records, or c)done both.
V (2009) plays this trope completely straight in the first season finale when Erica is able to waltz into the Visitor soldier gestation pool and destroy almost all of the soldier eggs with impunity. Why weren't any of the other fully grown soldiers guarding the chamber?
That can be justified, since the Big Bad was keeping it secret, and was worried about security breaches. But why wasn't there at least a lock?
Played with in Torchwood. Gwen Cooper traces the location of Torchwood by talking to a local pizza delivery place and had no problem entering their secret compound. The Torchwood staff finally admit they wanted to talk to her after they nearly bust up laughing at her "covert" entrance. It's later proven to be very difficult to get into (or out of) Torchwood Institute.
The Leverage team is very good in getting past security but they usually have studied the target extensively and do a lot of prep work first. However, in one episode when they are forced to improvise, they are able to lie, steal and bluff their way through three layers of security so Hardison can infiltrate the control tower of an airport. Hardison is allowed in even though the security badge he is using belongs to a female employee and the guards verify the picture on the badge against Hardison's face. They do not want to be politically incorrect to someone who just had a sex-change operation so they let him in. The consequences of this type of failed security are quickly lampshaded when Hardison almost causes an airliner to crash.
On Smallville, virtually any character on the show is prone to showing up at Luthor's mansion unannounced to have a chat with Lex in his office, steal something, beat him up, etc. Hence the alternate title being Lex Luthor Security. The wiki actually had a page on it. Not that any other supposedly secure location is any better. If a secret government base or LuthorCorp installation is mentioned, it's practically guaranteed that someone is going to break in, super-powered or not.
Lex himself once mentioned that he really needs to improve his security. (Fanatic) Apparently, he never got around to doing that.
One of Tess' minions also lampshades how cheap the security is.
On Las Vegas, The Montecito gets robbed in just about every other episode despite supposedly having the most sophisticated security in the world.
The Mayberry Bank in The Andy Griffith Show. The sole guard is an 80-year-old half-deaf geezer who spends all his time sleeping heavily and whose ancient WWI pistol falls to pieces if he takes it out. The teller and manager allow customers free reign of the place even when they're in the other room. People can waltz through the half-gate between the counter from the lobby without being stopped. The cash register drawers stand wide open with bundles of cash in full sight, as does the safe. And the safe can be entered by kicking a hole in the plaster wall of the hairdresser's shop adjacent to the bank. Of course, Mayberry doesn't need any effective bank security, what with its rock-bottom crime rate and genial, honest community — in fact, the only reason it was robbed in the first place was because an out-of-town robber overheard Barney ranting about the lax security in specific detail.
Fallout 2 has the Navarro Enclave Base, whose beyond laughable security measures consist of a guy who merely checks you for a password, and, with some modest BS skills, you can get almost total access to the entire facility (which barely has any locks, ID Scanners, or any other security measure you'd expect from a high tech base), whereupon you can loot pretty much everything and walk out with no one blinking an eye, even if you're walking out in one of their Powered Armor suits and toting over half their now depleted armory on your person.
The second and thirdResident Evil games take place in a zombie-filled city that's been barricaded by the US government. Despite this, people, vehicles, and attack helicopters regularly pass in and out without even seeing said blockade.
Although several semi-destroyed parts of Paragon City are sealed and only heroes above certain levels are allowed to enter, you can still find unpowered civilians — not ragged refugees, but people in obvious good clothes — constantly wandering around the ruins and cornered by gangs of superpowered thugs. Similarly, every door in the city will open to random passers-by, but heroes are not permitted entry unless they have a specific mission in the building.
Even more amusing when the civilian you had just rescued on the street enters the same building you were about to enter to clear it of bad guys.
And of course the same rules apply in City of Villains. Yup, you may be a psychopathic mass-murdering supervillain who eats people's souls for fun and profit, but trespassing... well, even you have standards, right?
In Mega Man games, this trope is played with. In some games you are able to just walk into Dr. Wily's fortress (some of the Mega Man X games actually teleport you into the final base). Some games avert this by requiring you to use your weapons to get inside and navigate some of the rooms. The "Magnet Beam" room from the first game and the platform hopping sequence to get in Sigma's front door in the first X series game are prime examples.
Gets particularly overdone in the Mega Man Battle Network series, as pretty much anyone can stroll into a secret base if they so desired. Sure, there is security, but unlocking it doesn't seem to be a hard task. Even after it's been shown people can actually lock a terminal from access. Only issue is the viruses.
MMBN could be considered the ultimate how-not-to guide for internet security.
Super Paper Mario: Mario and Luigi are able to sneak waltz into Bowser's castle just before he begins his invasion on the Mushroom Kingdom because he his minions forgot to lock the front gate. Whoopsie.
And that isn't the only Mario game where Mario is able to make it to Bowser's throne room with only minimal effort at the beginning of the game.
At one point: The man who built the wall that's supposed to stop you had to take a few shortcuts in building the wall (and tells you how to get past if you read his mind).
In Lunpa, you have an invisibility spell, and in the second game's Kibombo Mountain sequence, it's indicated that Piers took out a lot the guards before you arrived. Golden Sun was generally pretty good about that.
Sam manages to sneak into the CIA. The Cut Scene shows him using a fake ID and regular clothes before shedding it for his stealth suit. For some reason, the CIA has plenty of dark areas for him to lurk in. In the PC version, he sneaks in from the lawn, using big, obvious fan vents. One of them he can simply slide up. The other one somebody left open.
Lampshaded when Sam asks how he's going to get his kidnap target off the premises: Lambert reminds him that Fishers support team pulling up to the loading dock in a black van is perfectly legit, so long as nobody spots Fisher as he climbs in the back.
Team Fortress 2: many of the capture-the-flag maps are basically military outposts disguised as lumber mills or grain silos and, minus the multitude of mercenaries, they have the worst security measures ever. Besides having all the doors left wide open (including one that looks like it could withstand a missile blast) and the intelligence just sitting on a desk in an empty room, there are lit-up signs pointing towards the intelligence. It's like they WANT it to get stolen.
Let's not forget the indestructible rail tracks and elevators that appear to be designed just for the purpose of letting the attacking team escort a bomb into an empty missile bay.
The fan-made map CP-Steel mostly avoids this trope by making the base capturable by opening the outer doors and eventually extending bridges, or being able to jump a bottomless pit.
Played for Laughs in Breath of Fire III at the McNeil Mansion. When trying to sneak in, you find a broken wall that they just fixed... poorly enough that when Rei leans on it, it falls over. Half the guards are either scared stiff or total screwoffs who don't care if you sneak in, same with the servants... one of whom even lets you use his bed as a Trauma Inn. Rei even lampshades this at one point.
In Star Wars Battlefront, on Hoth. If the Empire tries to take Echo Base with a frontal assault, they're in for a fight. If a trooper takes a couple of minutes to circle around and enter from the hangar, he can often capture the entire base without firing a shot.
Played with on Endor with the Rebels. If you take a speeder and travel all the way around the map, and as long as no one sees you, you can pretty much waltz right into their shield generator building.
In Modern Warfare 2's Highrise map (depending on how skilled your opponents are) few people pay attention to the lower levels; this makes it somewhat easy to slip into the opponents base and start gunning down snipers focused at the map's center. There are a few points in other maps like this, but this is the most prominent.
In BlazBlue, pretty much anyone who ends up getting lost seems to find their way into Rachel Alucard's mansion. Despite her claims it should be much harder to find/access. "How did you get in here?" is practically her catchphrase.
The Penny Arcade comic used to illustrate the trope refers to Mass Effect 1, and it's actually rather justified. Any and all secure locks and computers can be hacked either by playing a "Simon Says" Mini-Game or by slathering the aforementioned slime onto it, a paste of nanomachines known in the game as omni-gel produced by breaking down unneeded armor and weapons. This simulates the process of doing some mental gymnastics to hotwire the device or using some gel to craft a perfectly suited "tool" - and characters can't even attempt to do either without the prerequisite L33t electronic or decryption skills.
It's played straight yet again in Mass Effect 2, using two different types of matching games to hack things. It's also lampshaded in the Downloadable ContentLair Of The Shadow Broker.
Shepard: "Remember the good old days when you could just slap omni-gel on everything?"
Liara: "That security upgrade made a lot of people unhappy. "
Many times in the Pokémon series. It's understandable, given the capabilities of the villainous teams, but it gets ridiculous sometimes. Hell, it gets even more ridiculous with Team Galactic, as not only do they not make any attempts whatsoever to conceal the location of their bases, nor make them discreet, but the receptionists and all the other Mooks in the main lobby won't even act like you're slightly out of the ordinary. Hell, there's a locked door with a guard next to it, and once you find the key card and open the door that is clearly to remain closed off to outsiders, the guard continues to justsitthere.
A particularly bad example in X and Y, where when defeating a pair of Mooks when searching for the entrance to their secret base, one of them loudly talk herself hoping that you don't find a secret door hidden in the room, while another loudly talks to himself hoping you don't figure out the password by openly reciting the password.
In Deus Ex and Deus Ex: Human Revolution most enemy bases are properly guarded. But somehow they always let some Data Cube or PDA with the passwords to their security systems lay around.
Truth in Television: Ask anyone who has to work with IT security, and they'll tell you that some people really are careless with their passwords. One example in Human Revolution has an irate lab worker on the phone with security, demanding a new access card immediately, seemingly oblivious to the obvious danger there is in having a loose card out for a high-security lab.
Ninth Rock begins with Spencer "sneaking" into MASA, even though the door isn't locked. There are guards in the inner parts of the building, but they're crazyFat Idiots and are hardly a hassle.
In the Civil War quest line of The Elder Scrolls V: Skyrim, you can eventually rise to the second-highest ranked officer in all of Skyrim in either the Stormcloaks or the Imperial Legion and become notorious for being a super-elite soldier who wins pivotal battles nearly single-handed, and you can still waltz right into the enemy's capitol— in your uniform, if you want— high-fiving enemy soldiers and guardsmen the whole way in, and have a friendly chat with the enemy high commander.
Grand Theft Auto V has an early mission where Michael has to sneak into a software development place as it's preparing a massive public relations evet. He uses the 'stand by door' method described below to get in.
The military bases in Beyond Good & Evil, an old food factory and an old slaughterhouse, have some legendary bad security. Highlights includes:
Electrical box that just shut down the electricity if you kick them.
Mobile high voltage defenses, placed at key security checkpoints... Guarded by robots that explode pushed into them, destroying not only the robot (the only way to destroy some of them), but also the defense.
Buttons that can be pushed from a long distance with some high tech shuriken.
Drainage canals where humans can hide.
And that's before we get started on the sentinels...
El Goonish Shive: Elliot had no trouble breaking into the facility holding the Dewitchery Diamond. Recent evidence suggests that the whole thing was part of a Batman Gambit by Pandora Chaos Raven.
Nodwick: The title character gets the party into an enemy fortress by claiming that they are maintenance people. He comments that the Thieves Guild would be unstoppable if they invested in coveralls with 'Al' stenciled on them.
Nukees: At one point Gav breaks into a military base by claiming to be a pizza delivery boy.
The Gargoyles were able to access David Xanatos' castle on top of the Erie Building seemingly at will, though he probably could have stopped them if he wanted to. Sometimes, that was the point.
While the Gargoyles come and go as they please (since they can fly), Eliza was denied access to the castle at least once when she was on foot.
Dexter's Laboratory was always open to DeeDee, no matter how much security Dexter installed. At least he tries. In one episode he did manage to seal it off completely...but locked himself out in the process.
Lampshaded in the South Park "Imaginationland" three-parter:
"Why is it so easy for children to get inside the Pentagon?!"
Lampshaded in the I Am Not An Animal episode 'Home'. When the animals are trying to break back into the vivisection laboratory they are told that:
A klaxon sounds and all the security systems turn off, just as the guards all take a twenty minute break. For some reason.
Mind you, the Autobots were no better. By virtue of being on the small side, many were the times Laserbeak just flew in, and there was the time he rode in on an Autobot in tape mode. Soundwave managed to get himself carried in just as often.
The Superman: Doomsday animated movie had Lois Lane easily sneak into the most secure areas of Luthor's building and into his office, tranquilize him into unconsciousness, call up Jimmy Olsen to help her, both of them spend a few hours going through all his files, before finally dragging the unconscious (paranoid, ridiculously-intelligent, could lose everything if this got out) Luthor over to a retinal scanner and requiring nothing more than sticking his eye against the screen to get directly into a lab where Luthor's most dangerous, most secret project was going on.
In Exo Squad, a TV reporter has unescorted access to the bridge of the fleet's capital ship during military operations against Space Pirates. Geraldo Rivera has nothing on this guy...
Futurama has the Cryogenics Lab. Characters that have entered in the third millennium include Fry (multiple times), Nibbler, Bender (multiple times), and basically anyone who wants to be frozen for a thousand years or so (or wants that to happen to someone else). No one even seems to notice.
There are no examples of Batman's many hideout break-ins in the DCAU because he's Batman, so flimsy or top-notch security is all the same.
Although, break-ins to the Batcave (when not being used to just set up the new Robin) happen infrequently enough to be used to point out someone being a serious threat, without having devolved to the point of The Worf Effect quite yet.
But played straight in the pilot of Batman Beyond. Terry finds the Batcave just by fiddling with the clock that hides the entrance (a bat had gotten stuck in the clock face). For someone so paranoid about his identity, that was a severe lapse in competence.
In one episode of Jimmy Two-Shoes, Lucius goes through an elaborate, booby-trapped hall to a room guarded by a robotic hand that requires a complicated handshake to get past. Upon entering, Beezy walks in and gets a soda from the fridge.
Lucius: What is the point of having all the security of you just ignore it?!
My Little Pony: Friendship Is Magic has an odd example in the episode "It's About Time." Twilight Sparkle, Pinkie Pie, and Spike sneak into the Canterlot archives to seek a particular spell. While they make an effort to avoid the guards, Twilight forgets that as Celestia's personal student, she's already allowed entrance. So, when one finally spots Twilight and her friends, he helpfully unlocks the door. Later, Twilight's mentor Princess Celestia simply passes right by her and wishes her a "Happy Tuesday." Lampshaded by Twilight.
Twilight Sparkle: Why isn't anypony surprised to see me sneaking around in here?
Potentially justified by the episode's Aesop being about Twilight getting herself worked up over nothing.
In The Simpsons episode "Realty Bites", one item at a police auction is a pair of wrought-iron security gates confiscated from a drug kingpin named Johnny D. The gates are bulletproof, bombproof, and battering ram-resistant. How did Johnny D. get caught? He forgot to lock them.
In the Rugrats episode where Tommy and Chuckie are left behind in a toy store, Stu and Chaz go to the security guard for help looking for them. The guard doubts the babies could be in the store because the security system is top of the range and would have picked them up. He is right about the security system being top of the range and it actually does spot them several times. The problem was the guard wasn't paying attention to the monitors.
GAS STATION FOOD MARTS. Ever try stealing a candy bar?
Many chain stores don't put near as much effort into preventing shoplifting as they could, the reason being it would actually cost them more money than they lose to theft to take the preventative measures. Stores put a lot of effort into monitoring "Shrinkage" (How much product is lost to theft, damage, etc) and have a value that, as long as the shrink is less than that value, everything is a-okay.
Social Engineering. Just ask Kevin Mitnick, a famous hacker. For example, need to get inside a door that can only be opened with a card key? Just stand outside, wait for someone to come by, say something along the lines of "I'm new here" or "I'm having a bad day, my card was destroyed..." People are nice enough to open doors with no questions asked. That is just one example.
A particularly devious method is standing next to the door while holding a bunch of (seemingly) heavy boxes, or folders, etc. Not only will people be willing to help you, but will most likely assume you have the card and just can't reach it.
Many places where card access is given to people who haven't had any kind of security instruction have large signs actually instructing you to close the door in front of the next person. They don't work, of course (the real solution would be to actually train people).
Most companies very specifically warn their employees against this, but people rarely cooperate. No one wants to be the Jerk Ass who wouldn't let the poor new guy in.
Similar to the above examples, the easiest way to get a password is to ring the building and say "This is Tech Support - can I have your Username and Password?" Despite the fact that Tech Support will never say this (they'll usually have an Admin Password that allows them into all accounts) and that people are warned never to give this info out, it still works a lot of the time.
Some people will actually volunteer this information unprompted when they call tech support. The average person does not understand electronic security very well.
A hard hat and a clipboard will get you in anywhere.
An event in which a couple crashed a White House party pointed out this. The White House actually used to be like this regularly, up until after the presidency of Abraham Lincoln. It was how the Prez kept in touch with the people.
It was pretty easy to get into the White House after the Lincoln assassination, too. Charles Guiteau, the future assassin of President Garfield, was able to get several meetings with the President to discuss his supposed pending appointing as Ambassador to France, even though Garfield didn't know him from Adam.
Several Russian officials caught a lot of flak when a group of students revealed that they had broken into a Russian nuclear facility with almost zero effort. Once they got past the fences, they had free run of the place and took photos of everything they came across. Apparently there were no guards stationed at the facility or they all just decided to go on break.
While lobby guards keep an eye on who's coming into the lobby of a building, the building's employees and/or residents usually will politely hold the door open for anyone coming up behind who looks like they are coming in, too.