This isn't a hypothetical situation. The employee in question was Fred Watley of Spokane, and when the time came for his liver transplant, his new insurance company said no.
“Most people would assume that their coverage isn’t drastically changed when their employer switches insurance companies,” said Driscoll, D-Spokane. “Unfortunately Fred found one area that really is affected, but with his help we’re going to make sure it never happens again.”
Fred, with the help of his wife LiAnne, helped their insurance company realize that the waiting period shouldn't apply to them. Victorious, they weren't going to settle with just saving his life. When he got on his feet again, they set out to prevent others from running into the same life-threatening problem.
More about their story can be found here: Spokane family testifies for organ transplant coverage fix