I have. Do you mean the hand-jive thing? It started with a group of students in the audience just doing it at the end of one of the programmes and then it became a regular thing to be done behind the longer (Saturday, at the time) credits.
Why don't they announce the winner at the start of the game show? Think about it, if the person who didn't win already knew that, then they wouldn't have to sit around for the whole recording. They could be doing something else.