Sax, I witnessed a 'chain-vomit' on a Gravitron. It was horrible: the first kid lost it right away, all over the kid next to him so he blows lunch and so on and so on--and we're literally stuck to the walls while a half-dozen more followed suit. People staggered off white as sheets. Carnies had to hose it down . . . before I'd get back on.
I've always thought that was urban myth - thanks for the confirmation!
That sounds like the scene from "The Sandlot" where they chew tobacco on a carnival ride, with predictable results.