Perhaps the most potent distillation of Schmuck Bait was the History Eraser button from the episode "Space Madness". Ren puts Stimpy to guard said button, and tells him that something incredibly bad may or may not happen if someone were to press the button, so he must under absolutely no circumstances touch it. Ren leaves, and the annoying narrator promptly enters the scene with the following:
Narrator: Oh, how long can trusty Cadet Stimpy hold out? How can he possibly resist the diabolical urge to push the button that could erase his very existence? Will his tortured mind give in to its uncontrollable desires? Can he withstand the temptation to push the button that, even now, beckons him ever closer? Will he succumb to the maddening urge to eradicate history? At the mere!push! of a single!button! The beautiful shiny button! The jolly candy-like button! Will he hold out, folks? Can he hold out? Stimpy: ... NO I CAN'T!!!(beep) Narrator: Tune in next week fo—
"Don't Whizz On the Electric Fence!"
In the Ben 10 episode "Tourist Trap", IT looks like a harmless, gigantic ball of rubber bands, despite the build-up to IT appearing, and the numerous warning signs surrounding it. Thinking someone's pulled a fast one on them, Ben decides to have his own brand of fun with IT, and his normally-more-sensible cousin Gwen doesn't even try to stop him. This releases the Monster of the Week to wreak havoc, simply because that's how the freakin' thing amuses itself. The conclusion of the episode implies that after the creature has been released, gone on a rampage, duplicated itself, rampaged more, fought Ben, continued to cause destruction, nearly killed people, and, oh yeah, more rampaging, until it was finally captured... Absolutely nothing about how this thing was contained will be changed. Everything will be fine, the mayor insists, "so long as people mind the signs." At least this time the creatures are put inside a giant lightbulb, where the crazed little suckers are easily visible.
Subverted in a Garfield Special where a young girl and a cat live in a Utopia of a garden. The garden also contains a box which they are warned they must never ever open. After a moment of temptation, they never ever open the box and live happily ever after.
This is based on a book of stories on Garfield's previous (and one future) lives, in which the same thing happens.
In an episode, Garfield is trapped in a Haunted House and finds a rope hanging from the ceiling with a sign that says "DO NOT PULL ROPE." Naturally, he pulls on it and is dropped through a trap door. "There's your lesson for today, kids. When it says 'Don't Pull The Rope,' don't pull the rope."
In another episode he sees a door with a sign: "Beware of the SPLUT!". He opens it and gets a Pie in the Face. *SPLUT*. Later on he has been sent to Samoa and sees a similar door with "Beware of the GORSH!". He opens it. Turns out that gorsh is the Samoan equivalent to splut.
In yet another episode, Binky gives him a present labeled "Warning: Splut Enclosed". He had apparently known what it was, but forgot, so he opened the present and was promptly splutted.
A Halloween special has the Super-Fun-Happy-Slide lever near the top of a staircase in Burns' vampire mansion. Having just run up the stairs to escape the vampires in the basement, Bart even lampshades the fact that it's Schmuck Bait: "I know I probably shouldn't, but when am I gonna come back here?"
"What is your fascination with my forbidden closet of mystery?"
Daddy's soul doughnut, Do not eat: "Mmm... forbidden doughnut."
Actually referred to by name in "The Great Simpsina" by the son of a rival magician who tricks Lisa into revealing her mentor's secret of the milk can escape trick.
Peter is in a bland room with a button accompanied by a sign warning not to push the button. He pushes it. An old kung fu master, wearing a traditional martial arts outfit, walks into the room, bows politely, and beats Peter senseless.
Upon staring at a lever labelled DO NOT PULL on an airplane door, Peter proceeds to do so, decompresses the entire plane and falls to his death giggling.
"Ooh - piece 'o candy. Ooh - piece o' candy." James Woods fell for that one twice.
When offered a free boat, or the contents of a box, Peter opts for the box because anything could be inside it, even a boat like they wanted!
In El Tigre Manny and Frida find a chest covered in warning signs with a skull shaped lock. They declare "It's like an us trap" and consider that it might be a test before immediately disregarding their concerns and crack it open. Unlike most cases of this trope bad things don't immediately happen when the Artifact of Doom is unleashed. It's only when they trick Manny's mom into putting it on to resume her abandoned superhero identity that things get out of control.
In My Little Pony: Twinkle Wish Adventure, the mayor gives Cheerilee the box containing Twinkle Wish, the sleeping wishing star, and warns her that it must not be opened until the next day at sunset, and even tells her "The fate of the entire festival is in your hands." Quite naturally, the box ends up opened mere minutes later, and Twinkle Wish is snatched away by a passing dragon.
Free ACME Bird Seed. OTOH, it's subverted each time since the Coyote is the schmuck, rather than the Road Runner.
In "Design For Leaving", Daffy Duck is a salesman who converts Elmer Fudd's house into a computerized push-button house. One of the buttons is a red one that Daffy tells him never to press ("Not the wed wone!"). Eventually, after Elmer gets frustrated and throws Daffy out (with the help of a "push-button salesman ejector"), he caves in to his curiousity and pushes the red button. It's an "In Case of Tidal Wave" button that raises the house up on a gigantic hydraulic pillar. Daffy comes by in a helicopter, offering to sell Elmer a little blue button that'll get him down.
In "Hare Remover", Elmer tried to capture a rabbit to use as a test subject for a formula. He decided to use the trick of the box that shuts down when someone pulls the stick. The trick was so old Bugs commented having heard about them from his grandfather and not believing (until then) he'd see one himself. He deliberately fell for it so whoever bothered setting it wouldn't feel disappointed.
In Batman: The Brave and the Bold, a button in the Batmobile dispenses sleeping gas onto whoever presses it. Joker naturally presses it, despite being warned against it. He does it again later.
In Rocko's Modern Life when Rocko's boss is on leave leaving Rocko in charge of the comic book store, he tells him not to touch the green button on his office chair. Rocko develops the urge to press the button which he did. It starts out as a massage later transforming Rocko into an evil boss.
Aang:(to Zuko) You had to pick up the glowing egg...
Dexter's Laboratory, "Trick or Treehouse": Dexter sneaks into Dee-Dee's treehouse and finds nothing but a lever and a sign saying "Do not pull." He lampshades this ("Who does she think she is with this lever, me?") before pulling the lever and promptly gets trapped in a breadbox.
George of the Jungle: Tom Slick once saw a detour sign telling him to go through a tunnel. As he noticed Baron Otto Matic's henchman with a can of paint, Tom assumed he should take the route blocked by the sign, but found a rock blocking that path.
"In the name of all that is holy, don't connect the red wire to the blue wire. Thanks."
In an episode of Pinky and the Brain, the pair are in a nondescript foreign country. Pinky has a book full of wacky gestures that are extremely offensive to the locals, all of which are labeled "never, ever do this" or similar. Needless to say, he feels the need to perform each gesture as he reads them, and Hilarity Ensues.
Mr Bogus: A literal example of bait happens in the third act of the episode "Battle Action Bogus", where Bogus uses this as part of a trap to dispatch both Ratty and Mole.
In the episode of The Real Ghostbusters "Knock, Knock", a group of excavators working under the city come across a door with a demonic face on it that warns them, "Do not open until doomsday!" Guess what they do? (This is lampshaded at the end when the heroes manage to close it after a rather dangerous battle, and Venkman says, "That was fun, can we do it again?" When the door repeats its warning, he quickly adds, "Just kidding!")