There is always a small but skeptical part of the population that thinks all game shows are "rigged." The problemo is, WHY rig a game show? It's done for the purpose of delivering advertisers an audience, and that audience wants to watch a fun show, which is easy to produce without "rigging." There is no incentive for the producers to rig the game. In fact, there is a HUGE DIS-incentive. Rig it and do time.
TPIR does select contestants whom they think will produce the best TV, so some who show up have no chance of doing anything other than remaining in the audience. If that's "rigging" to you, then that's your choice. But the production company, which has a fortune at stake, takes great pains to run an honest game show.
Michael