It's a familiar scenario. Kid wants something from parent they know won't be easy to get. The first argument they make is almost always, "Everybody else is going to that concert!"/ "All my friends have this body part pierced!"/ "Everyone at my school is wearing one!" or something similar.
The first rebuttal the parent makes in defense will inevitably be, "So, if the whole world/ your whole school/ all your friends were going to jump off a bridge, would you jump, too?"
The response will most likely be one of three, in increasing order of frequency:
Perfect set-up for a You Are Grounded or Can't Get Away with Nuthin' . Pertains to Peer Pressure Makes You Evil.
Variations occur where the players are not parents and children, but the pattern is always the same. "Cliff" may also be substituted for "bridge." Another variation is "If X told you to jump off a cliff, would you?" or "If all your friends stuck their heads in the oven, would you do it?"
For a brief period in the 90s, the most common response was to say something along the lines of "No, bridge-jumping is tomorrow," and explain that the kid character was also participating in bungee jumping.
Contrast The Complainer Is Always Wrong.
Turns up in Batwoman when Kate and her father (who knows her secret identity) argue over whether she should take time to recover from being drugged in her last fight.
Kate: Alice [the villain] isn't taking the night off, Colonel.
Colonel Kane: And if Alice jumped off a bridge?
Kate: I'd be right behind her. You're such a Dad.
In the Harry Potter fanfic Fire Burns, Katherine and Remus have an arguement over Katherine having killed someone on Voldemort's orders.
Remus: If someone told you to jump off a bridge would you do it?
Katherine: I'd ask them to demonstrate.
In the My Little Pony Friendship Is Magic fanfic First Snow, in response to Diamond Tiara wanting a really glittery dress and claiming that everypony in school would have one (probably not), Filthy Rich asks his daughter that if all her classmates jumped off a bridge, would she? Her answer is that if the Cutie Mark Crusaders did, then no, but since her actual friends aren't stupid, doing so would either be safe or they'd have a good reason to.
Film - Animated
Antz: Z tries to stop the foreman from finishing a tunnel that leads to a lake, which will flood the entire colony by asking him this. As the foreman considers it thoughtfully, Z comments that he's asking the wrong guy.
Coneheads: Beldar Conehead's reaction at his daughter, Connie's fake tattoo on her cone.
Connie: It's just a decal, everyone's wearing them.
Beldar: If everyone jumped into a bitumious cauldron, would you jump in too?
Connie: I am not a little cone anymore, dad!
Suicide Club: Proven. The whole movie is about a wave of suicides among schoolchildren all over the country for seemingly no apparent reason. A group of school-kids are on the roof talking about the recent wave of suicides. One says, "We should kill ourselves too!" Guess what happens? The whole lot of them end up jumping off the building. One girl left who's too scared ends up dragging a friend along screaming "Now we have to! We have to!" Turns out the current hot idol band is sending subliminal messages in their songs encouraging young people to kill themselves. They never explain why, but it's Japanese cinema, what do you expect?
There's a joke which responds to the question with "I'm a lifeguard."
An old Smothers Brothers routine:
Dick: You wouldn't jump off a bridge just because your friends did, would you?
George's mother: I suppose if Johnny Finnegan jumped off the Empire State Building, you would have to jump off the Empire State Building, right?
Jessi Ramsey says in one of the Baby Sitters Club books that this is one of her mother's favorite arguments.
Subversion in this snippet from a conversation in Catch-22:
"Suppose everyone thought that way."
"Then I'd be a damned fool to think otherwise!"
In Dan Abnett's Warhammer 40,000Gaunt's Ghosts novel Ghostmaker, Bragg is asked if the Ghosts would jump off a cliff if Gaunt told them to and says yes, of course, is that a trick question? Bragg, while not the sharpest knife in the drawer, is deliberately playing up his Big Guy role to convince them he's The Fool because he knows one is The Mole.
Live Action TV
Straight example in My Brother And Me: D.D. wants a haircut like his two best friends are getting.
His Mother: So? If the two of them were going to jump off a bridge, would you jump, too?
Melanie:(big sister) Do you have to ask? You know he would.
The Fresh Prince of Bel-Air: Will tells his uncle's jerk of a rival to "Drop dead!" and he suffers a fatal heart attack right then and there.
Will: Come on, man! If I told you to jump off a bridge, would you do it?!
An episode of The Bill featured Diane Noble trying to talk down a daredevil kid from jumping off a bridge. At one point she says "If everyone else jumped off... never mind."
Jane: Let me ask you something. If Director Bertram wanted a CBI presence to jump off a cliff, would you and your CBI presence jump off that cliff?
Lisbon: If there was overtime, sure.
When The Osbournes had their reality program, Jack went to the beach with some friends who all thought it would be fun to jump off a pier. Jack did it, landed wrong, broke his arm and had to call his mom from the hospital. Sharon asked "Why did you do that?". Jack answered "Because all my friends were doing it." Sharon probably realized asking the stock phrase would be rather foolish.
Don Ramón: You're so obedient (El Chavo shows pride over this). And if I tell to jump off a bridge, you would do it?
Chavo: I'm obedient, not retarded.
The Golden Girls features an inversion in that the (middle aged) child gives the rebuttal to their parent. It doesn't work.
Dorothy: Ma, did you sleep with Tony Devlecio? Sophia: A little. Dorothy: Ma! Sophia: Blanche made me do it! Dorothy: Don't you have a mind of your own? If Gladys Goldfein told you to drink an entire bottle of keopectate would you? Sophia: Who blabbed?
A young Dilbert very effectively responds to this argument after his mother will not allow him to go to the skate park with his friends. "Well, that would depend on many factors, including height, training, and equipment. But if 100% of the people enjoyed it, as in my skateboard example, then I would conclude it was safe. A better question might have been 'If everyone else wore clothes, would you do that?'"
The comic strip Zits which deals primarily with teen-parent relationships seems to enjoy this trope. Jeremy's rebuttals to the question of jumping off a bridge have included: "For a free T-Shirt? Yeah!", "No, but I might be tempted to push you over" and "If it kept me from hearing that stupid cliché again, I'd be first in line."
The book Garfield's Insults, Put-Downs, and Slams lists the following rebuttals:
Rat: And if neighbor Bob jumped off a ten-story building, what would you do?
Pig: I'd take his lawn mower.
CM Punk to Kevin Nash: "You don't have to answer this; it's a rhetorical question: If Triple H asked you to jump off a bridge, would you? Because I think that would be good for business."
Old Harry's Game, the sitcom set in Hell. Thomas is talking to a woman who killed herself because she listened to him when to told her to commit fraud and was subsequently arrested (or something like that). He denies responsibility "If I told you to put your head in the oven... OK bad example".
Lemming Mother: All the other kids have got a scooter and that's why you need one, too? And if all the other kids jumped off a cliff... erm... okay, you get the scooter.
xkcd#1170: Countered by assessing the hypothetical situation more realistically than intended and saying that the most likely explanation would be that the bridge was on fire.
Rugrats: A variation occurs in the episode "Driving Miss Angelica", where Angelica has successfully tricked Chuckie into being her slave, and she now blames him when her orders have gotten them trapped in a closet.
Chuckie: But, Angelica, you ordered me to come up here.
Angelica: Do you always do everything I tell you? If I told you to jump off a bridge, would you?!
An episode had a Running Gag of his parents constantly saying this to him, with Bobby responding with things like "Well, if I was hot, I might..." At the end of the episode, he wants them to go by the bridge so he can "see all the action".
Elise: Okay, but we're having salad for dinner. Chris: ...Dan said we were having burgers. Elise: If Dan jumped off a cliff, would you? Chris:[actually has to think about it] Elise:[horrified] Chris! Chris:[stammers] I-uh-I mean, it depends. Elise: Don't jump off a cliff! Chris: Well, I wasn't planning on it. Elise: But if Dan jumped, you would? Chris:[actually has to think about it again] Elise:CHRIS!!
The Legend of Tarzan: A kid injures himself after trying to imitate Tarzan, citing his ability to jump from the top of a waterfall and land safely. His aunt begins to ask the question before realizing it's a poor example.
Buford/Bufavulous: Mother always told me if all the other kids were jumping off a cliff, I should to.
Baljeet/Baljeetolas: Your mother said that?
Buford/Bufavulous: She was not a nurturer. Let's go! (jumps)
In a Darkwing Duck episode while DW is under the effect of a Love Potion (which makes him all buddy/buddy with NegaDuck), Negaduck tells him to jump off a cliff, so he does. He even yells Geronimo on his way down.
Negaduck: And to think, all this time all I had to do was ask.