Over on his weblog, which I cannot recommend often enough, Ken Levine often writes about joke stealing. Sometimes, it's a coincidence. Sometimes, it's a crime punishable by death or working for basic cable, whichever's worse. Anyway, I only have about 900 anecdotes on the topic. Here's one…
As you may remember if you watched Welcome Back, Kotter, each episode used to open and close with Gabe Kaplan telling someone (his wife, usually) a very old joke. That was kind of the point of the segments; that Mr. Kotter had all these real old jokes…the kind that belong to no one, that people just tell one another.
The jokes were often not written into the script. If they were connected with the storyline of that particular episode, they were. But if not, they'd be handled as follows: Before it came time to tape one, we (the writers) would tell Gabe a couple of jokes and he'd pick one. Then he'd go out and "wing it," telling the joke to, say, Marcia Strassman, who played his spouse. Kaplan's delivery was usually better if he was just doing the joke from memory, putting it into his own words, and Marcia's reaction would be more natural because she hadn't heard the joke in rehearsals.
So in one episode we gave Gabe the hoary line about the guy who was so paranoid that when he went to a football game and the players got into a huddle, he thought they were all talking about him. This is an ancient joke that was probably heckled in some form at the Parthenon. The day after that show aired, we got a hysterical call from a then-semi-prominent (today, largely forgotten) stand-up comic. That joke was from his act, he said. That was his joke and he was demanding the address of the writer who'd written that episode because he was going to sue the thief into oblivion.
Our producer explained to the comic that, first of all, the credited writer of that episode hadn't written that joke. And secondly, no one who lived in the current century had written that joke. The comedian calmed down…but only a little. He agreed to not pursue legal action but warned that he would if ever again, one of "his" jokes was purloined for our show.
Fade out, fade in. A week later. Another show had aired. Another old joke in the ending…I don't recall what it was but the comedian was back on the phone, screaming that we'd stolen it from his act. Again, the producer told him that the joke was public domain and that it wasn't his. "If you want to spend the money on a lawyer and sue us, I can't stop you," he told the guy. "But our lawyer will just find a clip where some comic did that joke on The Ed Sullivan Show in 1955 and you'll lose and look ridiculous!" The comedian cussed and hung up in anger…and two weeks later, he was back again with the same complaint. We'd stolen a joke from his act.
This went on half the season. The comic kept calling with threats. Finally, one of our other producers took one of the calls and this is what he said: "Okay, you're right. We have a tape here of your act and each week, we play the tape and pick a joke to use. We've already taken the best ones and we were going to stop and let you keep the rest. But you're pissing us off with these calls so we're going to keep taking jokes until you have no act left at all."
The comedian said, "Oh, please, don't! I won't call again!" He hung up and that was the last we heard from the guy…and I mean that literally. I don't think I ever saw him perform anywhere ever again. I have the feeling that he's working somewhere waiting tables and when people recognize him and ask, "Why aren't you on TV anymore?," he tells them, "Welcome Back, Kotter stole my act."