To add to what audience members have said in the past, some are required to sign contracts, vowing that they won't say much about what they saw after they have filmed and watched the show. That could just be because they don't want any spoilers getting out before the show actually hits TV, or because the show is fake and the audience is actually a part of the act too.
Interesting, I've heard of them doing things like that on Game Shows, but not on Talk Shows. A friend of mine won $10k on The Price Is Right, and he wasn't allowed to talk about it until the show aired. But in addition to that, they withheld his prize money until the show aired, I guess as an incentive to keep his mouth shut. Perhaps on the talk shows, they refrain from paying the guest in a similar fashion, until the show airs?
They do the same thing on those psychic medium shows. They make he audience members sign a contract, but I am not sure if that is because the entire show is a fraud or because of spoilers. I wasn't aware that this was happening on game shows too. I can't believe they withheld your friend's money until the show aired lol. pretty good way of shutting someone up though.
I was also thinking that I wonder if it has anything to do with the show recouping their prize money with the money received from the advertisers first. In other words, do the contestants still get paid if the show unexpectedly gets dropped and never airs? Perhaps just me being paranoid, and I suppose it's a long shot of an idea. I guess we would have hear more uproar about stuff like that if it really happened by now.
Good guess, but I have absolutely no idea as to whether they wait until they get their money from sponsors and advertisers before they pay winners. When I first heard about those medium shows making people swear to secrecy via contract, I automatically assumed that the mediums were not really mediums and that everything was fake, and that was why the audience were being made to keep quiet.