A few seasons back, I believe it was the season of the NBC pilot episodes, the Seinfeld studio audience was developing the annoying habit of whooping it up every time Kramer entered the scene.
Anyone familiar with the old Happy Days series has seen how this happens. First the most popular character (the Fonz, in that case) gets a big ovation when they enter. Then it spreads to the rest of the cast, and eventually you have about half the show's running time on hold as the actors wait for the audience to shut up.
The worst current offender I've seen is Married...With Children.
But thankfully on Seinfeld it stopped not long after it started, and I've always wondered how that occurred. It seems to me there would be no way of ending it once it begins without making a point of it, for example issuing explicit instructions to the audience as they come in to keep it down, or going exclusively with canned laughter.
Does Seinfeld have a live audience any more?