The Eleventh Doctor: [sarcastically] Oh yeah, yeah, of course! It's an interdimensional multiform from outer space; they're all terrified of wood.
When characters attempt to physically seal off access to a room, passageway or building, but are doomed to fail miserably due to poor choice of materials or bad tactical planning.
This trope can come in many flavors. A person on the run from a killer may choose to block a door with light and easily movable objects. Other times, Myopic Architecture can easily come into play; characters may put a serious effort into blocking a single door in a room with multiple exits and/or easily breakable windows. In comedic situations, the ineffective barricade may come in the form of what amounts to a (quite surmountable) waist high fence, or the character in question could simply forget that the door he's trying to block opens outward instead of inward (like in the trope image).note
This can also be seen when multiple characters are making serious attempts at fashioning a barricade of some sort, while one of their companions piles on extremely light objects like pillows or potted plants or else is steadily deconstructing their barrier in order to make his own. Occasions like these can at times serve as a lesson to not allow the Cloudcuckoolander to assist in defense planning.
A common comedic situation tends to occur where the barricade is being built, but the builders turn around and find that they have sealed themselves inside with what they were trying to escape. Sometimes the thing they were trying to escape may have even helped them construct the barricade while they weren't looking. Either way, Hilarity Ensues. The Rule of Funny aspect of this trope is really played up, however, when what is an obvious Absurdly Ineffective Barricade is shown to actually work. In these cases, the barricade builders are often just as surprised as anyone else.
While the Absurdly Ineffective Barricade is often Played for Laughs, it can sometimes be used to show the effects of panic on a terrified character on the run. In the latter cases, the poor choice of defenses will often lead to the realization that the builder has made a fatal mistake... moments too late to do anything about it, of course.
Note that in order to qualify as an Absurdly Ineffective Barricade, there must be some obvious flaw on the part of the characters making it. If the defenses are well planned but the villain is powerful enough to burst through them anyway, it does not count. If the barricade itself is just fine, but the villain finds an inobvious way around it (say, through the nearby wall), that's not this trope, just Myopic Architecture.
- In Accident: Month One, Danny uses a rolling computer chair to keep his parents out of his room after a very embarrassing encounter with them at breakfast. It fails epically.
- In 28 Weeks Later, a safe room turns out to have a back door.
- In Abbott and Costello Meet Frankenstein, the duo attempts to keep the rampaging monster out of their refuge by pushing a heavy bed up against the door. Unfortunately, the door opens the other way. They also once tried to barricade a door with their own bodies, in the end it didn't work...because there were no walls.
- In Czech filmmaker Jan Svankmajer's film Alice, Alice does this to the White Rabbit to keep him from seeing her when she's very large. Then he starts throwing rocks through the window.
- Aliens. The survivors rebuild the barricades that failed to keep the Xenomorphs out of the Operations Centre and supplement them with robot sentry guns. They get in through the ceiling.
- In the Bean movie, Bean, having accidentally defaced Whistler's Mother, locks the door and drags a plant pot in front of it to keep out the curator. A couple of seconds later, the curator enters via another door, right next to the one Bean locked.
- The Big Lebowski: After suffering multiple home invasions, the Dude gets kinda sick of it and carefully creates a barricade on his door by wedging a chair between it and a plank of wood nailed to the floor. When the home invaders return, it's revealed that the door opens outward, making the barricade completely useless. To add insult to injury, the Dude later trips on the plank still nailed in front of his door.
- In The Blues Brothers, at the end as the titular characters were going to deliver the 5 grand to the Cook County assessor's office, they did this to the lobby of the building they were in...to keep out the army. Bonus points for doing it again with office furniture to blockade the assessor's glass door and wall.
- In Candleshoe, the group does the usual "toss the villains out and move the furniture to block the door" stunt, but the baddies reappear through the open door at the opposite end of the room.
- Unintentional example in the z-grade horror film The Curse of Bigfoot, where the main characters prepare to ambush and fire-bomb the titular creature by constructing a formidable and inflammable fortification consisting of...a stack of about three or four bales of hay in an open field.
- In Dead Air, after the crew of a late-night radio talk show realizes that their building is smack in the middle of a Technically Living Zombie Apocalypse, they all decide to start barricading the doors to their studio. While the male crew members are stacking up heavy tables and filing cabinets, the show's producer contributes by setting a small potted plant on the pile.
Logan: Lucy... and what exactly is that supposed to accomplish?
Lucy: [walking off] Fuck you!
- From Gone with the Wind, as the main characters flee Atlanta ahead of the Union army:
Scarlett: Wait, I forgot to lock the door! ... What are you laughing at?
Rhett: You, locking the Yankees out!
- Jay and Silent Bob Strike Back: during the chase around the Miramax lot, the titular pair place a small trash can in front of one of the doors before fleeing. Although to be fair, one of the security guards does smack his shin into it and limps around for a moment.
- The Knack...and How to Get It - protagonist Colin attempts to bar ladies man housemate Tolen from the house by nailing a 1x2 strip of wood across the door frame. Echoing the trope in The Young Ones (see TV), new housemate Tom, who is quite mad, paints his room completely white, including the windowpanes, justifying it as protection from The Bomb.
- In The Last Lovecraft: Relic of Cthulhu our "heroes" are trapped in a small RV, when one of the monsters from the deep smashes through the window all they can do is close a flimsy fold out wooden screen to slow it down.
- The Lord of the Rings: Almost happened in The Fellowship of the Ring: after Aragorn and Boromir barricade the doors of Balin's Tomb with sturdy Dwarven axes, Legolas adds a thin and completely useless wooden stick to the barricade. This prompts the cast to break character and start laughing on the "typical elf work". Naturally, this did not make the final cut, but you can watch it here.
- Man of Steel: After Superman tells the civilians in the main street of Smallville to take shelter, there's a closeup of someone shutting the latch on a door, which wouldn't normally be an example of this trope except that we've just seen Superman and General Zod smash straight through several oil storage tanks and various buildings including a gas station.
- Pacific Rim sees the Jaeger program being defunded due to diminishing returns in fights against the Kaiju and being replaced by very tall concrete walls. This is 12 years after the Kaiju prove capable of smashing anything man-made. These prove to be even less effective at keeping the monsters out. And then the very idea of blocking Kaiju with a wall is proven pointless because of the appearance of Kaiju that can fly.
- In Scary Movie 3, the heroes are shown boarding over a cellar door to keep aliens out (in a parody of Signs). Cue Cindy opening the door with no problem. It turns out they'd just nailed some planks to it without fastening them to the wall.
- Naturally, this happens in Scooby-Doo 2: Monsters Unleashed. When Scooby and Shaggy are fleeing the Black Knight Ghost, they start barricading a door behind them only to realize that the Black Knight Ghost is in the room with them, helping them build it.
- In Signs, the family barricades all the doors and windows downstairs. Realizing they don't have enough wood to barricade all the upstairs windows, they instead barricade the doors of every upstairs room with a window. It's only after the aliens break into the attic that the family realizes they forgot to barricade the attic door.
- Also played with in the basement scene; after barricading an entrance with several large, heavy bags of dog food, one of the characters notices a single can of food rolling on the floor, and adds that to the barricade as well.
- The Thing (2011). One character hides from the Thing in a storeroom, protected only by a pair of swing doors. All he can do is stop them moving, in the hope that the alien monster won't realise someone has gone inside. It doesn't work.
- In Howard Hawks' The Thing from Another World, they barricade a door against the monster, but the door opens the other way.
- Threads. As World War III breaks out a family rushes to pile mattresses and blankets on top of a cellar door, only for the entire house to be obliterated by a multi-megaton nuclear blast.
- The Three Stooges shorts used this in a couple of varieties, including the door opening outwards and the villains coming in behind them, sometimes handing them things to put on the barricade.
- In UHF, Stanley Spadowski (Michael Richards) is being chased around the offices of Channel 8 News by the top exec's murderous thugs. He shuts himself into the top exec's office and barricades the one door with everything he can find, until the door is completely covered. He then collapses in exhaustion, but is proud of his quick thinking. They'll never get him now. The thugs then come through the conveniently large window.
- Done to a great effect in "The Last Virgin" vignette of Vedo Nudo - probably one of the earliest examples of outward/inward variety of the trope.
- World War Z. While on an airliner thousands of feet up in the air, the protagonist realises that passengers in the compartments behind have become infected and the only thing separating them from the rampaging flesh-eating zombies is a curtain. Everyone starts piling luggage in front of the curtain, only for a bag to fall through the curtain and give them away. Needless to say the barrier isn't very effective anyway.
- In 1812: The River of War, some of the soldiers defending the Capitol Building rip the doors off of one entrance to use them as material for barricading another entrance. After the stupidity of this is pointed out to them, they fix it by dragging two enormous statues to block the now empty doorway.
- Happens to a elderly wizard in The Light Fantastic; he knows that he is going to die soon, so he hides in a chest that's supposed to be magically sealed against Death. Unfortunately, he made it airtight, and he hears an ominous voice saying it's a bit stuffy in here.
- In Night Watch, Vimes wants some citizens to tear down their barricade RIGHT NOW...and rebuild it, because you can't just pile any old stuff together! Barricades have to be built!
- In Interesting Times, Cohen had seen a far eastern example of a grand wall surrounding a vast territory. He acknowledges it was grand and ponders the ladder possibilities in nearby trees.
- In the non-fiction book On Wings of Eagles the protagonists, U.S. businessmen escaping from the Iranian revolution, are in a van that's stopped at a revolutionary checkpoint. One man whispers, "Quick, lock the door!" causing his companion to repress some hysterical laughter, as the revolutionaries are armed with assault rifles that can easily shoot through the entire van.
- Serious example in A Song of Ice and Fire. Harren the Black spent three generations constructing the most impregnable castle imaginable, Harrenhal. On the very day it was finished, the Targaryens launched their invasion of Westeros...on dragon back. Dragons can fly, and their flaming breath is absurdly hot. Harrenhal has an interesting melted look to it now, and is considered cursed.
- Notably, in the web comic Tales of the Space South, Dickarus is able to climb easily through the zoo's "Impermeable Fence."
- Buffy the Vampire Slayer:
- In "Never Kill a Boy on the First Date", Xander and Willow lock themselves in a meeting room by shoving a couple of chairs in front of the door: so far so good. How do they reinforce this barricade? Chair cushions, and a lampshade.
- In the episode "Bewitched, Bothered, and Bewildered", after a spell gone awry has caused every girl in the school aside from Cordelia to fall madly in love with Xander, he attempts to take refuge in the school library by moving a library card catalog in front of the double doors that serve as the entrance. Since he apparently didn't realize that the doors open outward, Buffy in a coat (and not much else) calmly opens the doors and walks around the catalog◊ while Xander's back is turned.
- El Chapulín Colorado tried this by placing a plank in front of the door, only to be remainded that the door opens inward. And then when he opened the door to get inside, he tripped with the plank.
- Doctor Who:
- "Destiny of the Daleks": The Doctor and Romana take refuge behind a hastily cobbled together privacy screen. The Doctor says something like There, That Should Keep Them Out, and Romana sneers "That wouldn't keep out a determined mouse!"
- "The Christmas Invasion": Jackie and Mickey put a wardrobe in front of the bedroom door in an effort to keep a berserk Christmas tree from attacking them. Problem: The wardrobe is made of flimsy medium-density fiberboard, and the terrible tannenbaum just rips through it like balsa.
- "The Eleventh Hour": While Prisoner Zero, a hostile shapeshifting alien, is changing form behind a door that the Doctor locked with the sonic screwdriver, Amy asks if that will hold it. The Doctor sarcastically responds that it will because interdimensional alien multiforms are all "terrified of wood". Indeed, Prisoner Zero knocks down the door moments later.
- On Fargo Karl, the town lawyer, has been summoned by Lou to the police station to act as counsel for Ed. He goes despite the fact that he spent most of the night drinking and is extremely tipsy. After talking with Ed, Karl leaves the station just in time to see Bear Gerhardt and a posse of his men arrive with the intention of storming the station to free Charlie Gerhardt and lynch Ed. Karl runs back into the station and pushes a bench in front of the door to barricade it. The door is made out of glass AND it opens outward so the barricade is completely useless but Karl is too panicked and too drunk to realize that. Lou instantly recognizes that the station is indefensible and their only option is to distract the Gerhardts and sneak Ed out through the back.
- Game of Thrones: Played seriously and Up to Eleven in the backstory. Harren the Black spent thirty years constructing the most impregnable castle imaginable, but failed to account for his Targaryen neighbours invading with dragons. Harrenhal has a fascinating melted aspect to it now and is considered haunted and cursed.
- In one episode of Kenan & Kel, Rigby's becomes the setting of Ron Harper's accident, so the boys and Chris have to set up a barrier made of products to keep out irate basketball fans. At the end of the episode it's revealed how ineffectual this is, as the store's doors open outward.
- Monty Python's Flying Circus: during the "Upper-Class Twit of the Year" sketch, one of the competitions in the obstacle course is to jump a wall composed of matchboxes. The wall is three matchboxes high(roughly two inches). Subverted in that the Twits do end up taking a while to clear the jump.
- The sci-fi version happens in Star Trek: Voyager. An insane hologram is trying to kill B'Elanna, who shuts the door just in time, but the hologram just projects himself inside the room.
- Teen Wolf: While trapped in the school by the alpha werewolf, while most of the others are looking for ways to barricade the single door into the room, Stiles points out the very large wall of windows that could easily be crashed through.
- In one episode of That '70s Show Hyde does this. After it looks like Laurie is moving out and he's getting her room, she ends up staying. The end of the episode shows him standing there with the dresser up against the door telling her that she'll never get in. Cue Red opening the door outward.
- In Three's Company, Ralph Furley initally attempts to barricade a door with a sofa. Upon realizing that he lacks the physical strength to move said sofa, he opts instead to barricade the door with a single seat cushion.
- The Young Ones: In the episode "Bomb", Neil is standing next to an atomic bomb, and painting himself white "to deflect the blast."
- When Cecil rebels against the new management in Welcome to Night Vale his first move is to barricade himself inside his studio. Unfortunately, Cecil's idea of a barricade is a heap of cardboard signs reading "KEEP OUT!" and "SECRET ROOM!" in all caps, with an exclamation point.
- In Dawn of a New Age: Oldport Blues, the characters are assaulted by green fog that takes the form of snake-like apparitions that try to stab them. Ivy and a few others end up in one of the Home Ec rooms and try to barricade the door with a desk- except, as Simon points out, the snakes are fog and can easily slip through under the door (which is exactly what they do).
- In The Sydney Scroungers, there is an impromptu barricade of ludicrously expensive and comfortable Aeron chairs inside Wulagu's flagship. They burst into flame when the door gets torched open, making things even worse for the ones who put the barricade up.
- In the original version of Ao Oni, Megumi barricades herself in a room with most of the furniture. It looks effective at first glance... but Hiroshi can easily shove the ottoman blocking off the doorway aside, giving him room to slip right past her defenses. Good thing he's able to lock the door.
- In the zombie mod for Counter-Strike, the people with guns can shoot objects like sofas and vending machines to topple them in narrow doorways, making it much harder for the zombies to get through. In real life you would generally try to use your hands to move the objects out of the way, but if you're playing as a zombie and stabbing the sofa does not move it, then you're out of luck and will be slowly shot to death by humans as you ineffectively try to pass over it by repeatedly crouching and jumping. Conversely, the game engine makes some objects and forces rather wacky compared to real life, so that once the vending machine moves (for example by having another object pushed into it), it can actually end up flying across the room as if it was a mere tin can.
- Darkwood plays it for drama and terror. Properly barricading a hideout is way more complicated than just closing a door and putting a wardrobe behind it even dogs can push furniture out of the way with considerable ease.
- The Ghostfence from The Elder Scrolls III: Morrowind looks imposing enough, being a magical shield between towering stone pylons encircling the whole of the Red Mountain volcano. However, its effectiveness is undermined by the fact that Red Mountain dwarfs it completely, and that anyone (including the player) or anything can fly, levitate, or (with a magical boost) jump over it. Designed to contain the deranged Physical God Dagoth Ur and prevent his influence from spreading, it is implied to have actually served its purposes for several centuries before the game (with it being said that the fence once formed a "dome" over the entire volcano). However, as the power of the Dunmeri Tribunal has waned due to Dagoth Ur cutting them off from the source of their power within Red Mountain, the fence has faded into its current state. Blight storms from the volcano spread Dagoth Ur's Mystical Plague over the island, while his minions have tunneled under the Ghostfence to his ancient stronghold of Kogoruhn. Additionally, if one reads deeper into the lore, its implied that the Ghostfence isn't necessarily supposed to stop Dagoth Ur's influence and agents, rather, it is to present a metaphysical barrier against the encroaching power of the Sharmat.
- Fallout 4. Human enemies simply close and lock sturdy doors to create barriers against raiders and assassins, however if the player's leveled up in lockpicking, then these locked doors mean nothing. This is even acknowledged and lampshaded in magazines the player can find, where the author wonders if hairpins are more effective than proper lockpicks.
- In Half-Life 2, if you use a bunch of few-inch-high objects (like computers, computer monitors, & stools) to block an open doorway, combine soldiers can't figure out how to get in.
- In LEGO Jurassic World, Gennaro running to the outhouse doesn't exactly count (as an outhouse might provide protection from anything other than a T. Rex). What does count is the pathetic little wall of toilet paper rolls he builds once the T. Rex starts charging towards the outhouse.
- Pokémon Sun and Moon has a scene in Po Town where two Team Skull grunts have a barricade set up to keep intruders from waltzing on in. It seems like it could possibly be effective... if not for the hole in the bushes nearby that can be crawled through.
- In Resident Evil 2 and Resident Evil 3: Nemesis, there are pitifully weak barricades strewn about the streets and in the police station that likely failed to stop even a single zombie. It's entirely Played for Drama, since it's quite clear the police were horribly overwhelmed, panicked and underarmed, and dealing with a psychotic police chief who was actively sabotaging them so he could hunt them like animals for sport. In fact, some of the barricaded doors that block inaccessable areas of the police station early in Resident Evil 3: Nemesis (which takes place the day prior to 2) have since been cleanly removed by the time Leon and Claire show up.
- Riven has a sturdy-looking locked door barring access to a puzzle to the Player Character - who just crawls under it.
- In Undertale, the goofy skeleton sentry Papyrus is known for making fences and prisons with bars way too wide to stop anyone, let alone the tiny Player Character.
- DarkMatter2525: A recurring gag has the video start with Jeffrey needing to talk to God about a problem. While God is off playing with his toys or something, Jeffrey walks up to the door to God's room, the door guarded by security (wooden boards nailed to the doorway, surface-to-air missiles, a moat with sharks, etc.) only for Jeffrey to easily get passed the security due to a simple error (flying under the cloud floor, walking around the door since there are no walls, etc). One time he even straight up destroys the missile launcher with a kick.
- In Ménage à 3, Amber tries to barricade Dillon into his room when she wants some privacy. As he reveals in a later NSFW portion of the storyline, bedroom doors generally open inward.
- Problem Sleuth: "...before you can pry any [boards] off, the door swings open, away from the boards. It seems the boards never actually served to obstruct the door in the first place."
- The (unseen) barricade in this xkcd comic might've been good, but there was a glaring weakness nonetheless.
- The Amazing World of Gumball
- In episode "The Fight", Gumball is escaping Tina and builds an enormous barricade behind a wall that she instantly knocks down.
- "The Name" pulls a vehicular equivalent of the "door opens the wrong way" version: police set up a barricade of cars and a spike strip for a car reported as stolen, but the vehicle's path went along the front of the barricade instead of through it. Said car drove right past and the cops tore their own tires following.
- In Camp Lazlo, the Jelly Bean Scouts barricade the cabin door with planks to keep the Squirrel Scouts out. It's revealed that they took the planks from the back wall of the cabin, leaving a huge hole for the Squirrel Scouts to get through.
- In the Ed, Edd n Eddy episode "Home-Cooked Eds", the Eds try to barricade themselves in Eddy's house to keep out the Kanker Sisters, who have decided to take a vacation on Eddy's front lawn. Yet the Kankers somehow get into Eddy's house anyway.
- In the made-for-TV Felix the Cat cartoon "Instant Money", Rock Bottom is trying to get into Felix's house because Professor's counterfeited money was pouring into Felix's house due to a mishap on Rock's part. Felix slams the door in his face and immediately begins barricading the door to his house. Unfortunately, he left the window open, so Rock Bottom gets inside and helps Felix build the barricade until he realizes Rock is right behind him.
- One episode of Futurama sees Leela joining a group of activists protesting Planet Express's plans to mine an icy planet for oil. The protesters form a human ring around the front and sides of the company's ship to keep it from advancing...apparently forgetting that it can move in three dimensions. The crew promptly flies the ship up and over the protesters and continues on their merry way.
- In Happy Tree Friends, Sniffles is chased into a museum by an ever-growing crack because he stole a cursed idol. He uses various ancient artifacts from around the museum to block the door but the crack goes under the door and the artifacts fall into the crack.
- In a clip from 1935 called Little Black Sambo seen here, the titular character and his dog are trapped in their house by a tiger. They start piling up chairs and such in front of the door to keep the tiger out—but the tiger simply ties a rock on a rope to make it sound like he's still pounding on the front door, climbs in a window, and watches them continue building the barricade without even noticing him for a while, even handing the dog a few items to add to it before they realize he's inside with them.
- In the Looney Tunes Brother Brat, babysitter Porky is fleeing a vicious axe-wielding baby. He shuts himself behind a door and rapidly barricades it with every object in the room - including the waiting baby.
- Many episodes of Scooby-Doo involve the gang building a barricade, only to discover the door opens outward as opposed to inward. On at least one occasion, Shaggy and Scooby do this, and they don't immediately realize that the monster they're escaping entered from the opposite side of the room and is helping them build the barricade.
- In "Mystery Mask Mix-Up", the wall the door was in turns out to be movable, leading Shaggy to quip, "Wouldn't you know he'd be coming through the wall..." Also averted in "Spooky Space Kook" where Shaggy realizes a pile of chairs isn't going to hold the monster back and suggests that Scooby should try something else. It was played straight previously in the episode though.
- A hilarious subversion of the "sealed yourself in with the monster" situation, when Shaggy reveals that by removing a single item, the whole barricade collapses, allowing the gang to escape. Pretty smart of him since he has learned they often do get trapped with a monster.
- Then there is Scooby-Doo! Frankencreepy where Shaggy and Scooby try to avert this. Immediately after getting into the library they decide to board up every secret entrance in the room to prevent the monster from getting in. After doing so they then realize in their haste they forgot to lock the front door. Guess how the monster gets in.
- In The Simpsons, when a hurricane is approaching, Homer removes the back door of the house and nails it over the window, leaving the doorway without a door. It doesn't work very well.
- The house had perfectly serviceable shutters too, at least in that episode, which were just left to flap in the wind.
- Under attack by zombies, the family tries to barricade the windows. Homer forgot to barricade the front door.
- South Park
- In the episode "Butt Out", believing Kyle is going to sneak behind his back to steal the commercial position for the Anti-Smoking team, Cartman sneaks into Kyle's house to nail his bedroom door at night. It turns out not only was Kyle just getting back to his room after getting a glass of water, but the door opened the other way. This still didn't stop Cartman from boarding up the door once Kyle went into his room.
- The Shitty Wall built to keep outsiders out of South Park because they will kidnap their children. Goddamn Mongorians! Which is another poke at history: The townspeople hire the only Chinese member of their town to build the wall to keep out Mongolians, because they have so much experience doing so.
- In Somalia, US troops decided to use the much-vaunted 'sticky foam' to create a barrier against rioters. The Somalis watched in some puzzlement as the strange substance hardened into a barrier then they just climbed over it.
- In Port Arthur, a Victorian era prison town in Tasmania, there is a very impressive gatehouse to the military barracks... which you can bypass completely by going around the corner and stepping over a half-meter high wall.
- Schools, houses and such that have a waist-height gate with a lock... in a knee-height wall. Their purpose isn't to keep out someone who really wants to get in, but to keep anyone from claiming that they just didn't know they were on private property, and to keep very small children away from pools and other possible hazards.
- Fire code in most countries requires that almost all buildings open to the public have doors that open outward, so that panicked crowds cannot be trapped against them. This means absolutely none of them can be barricaded from the inside.
- In 2009, a group of NYU students barricaded themselves in a cafeteria by stacking lightweight tables and chairs at the entrance. When an elderly security guard had finally had enough of the ordeal, he simply started moving the chairs and tables out of the way while the students ineffectually yelled at him. Once he was able to walk through the barricade, the protest ended.
- In computer science, this is sometimes known as "picket fence" security. Even if there is a single password that is well known to everyone on the network, and it would not stop anyone who wanted to break in from doing so, the presence of security all by itself will keep people out due to simple respect. Such security systems are so named because it's like using a picket fence as protection for a house. It isn't going to stop anyone who wants really wants to break in; it's just there to indicate that access isn't freely allowed.
- France's Maginot Line against German invasion was based on the assumption that the Germans would not violate Belgium's neutrality if they wanted to invade France again. In 1940, the Wehrmacht put a decoy force opposite of the Line and launched the real invasion from... Belgium, soon cutting off the Line from the rest of France and leading to talk of an armistice.
- Then one of the decoy forces exploited the assumption behind the Line that the Germans would attack across a broad front as they had in previous wars ... by concentrating a large amount of force against a weak point in the Vosges.note And the Luftwaffe just flew right over the Line.
- Though in actuality, this was very much an Averted Trope. The Maginot Line was never intended to stop the main German Advance, rather to force them to go through Belgium, where the best French forces would be waiting for them, wearing them down while slowly retreating. This was based on the assumption that French could handle a war of attrition much better than the Germans. Something that would have proven very much correct. Though the Germans found a way around that basically no one could have anticipated, and an earlier French gamble failed spectacularly.