You can pretty say that about most of the guests in "reality" or "talk" shows. In fact I can figure out why they don't appear to have any clue about what normally happens on such shows, as if they've never watched them, but they must know at least a little bit or they wouldn't have come on the show at all... but on the other hand if they *did* know, then they definitely would refuse to appear to be on it.
Just a few other examples:
Survivor: So many guests coming to stay on an ISLAND who don't know how to swim, or they wear clothing that is really unsuitable for "surviving".
Jerry Springer: People being brought on the show because their spouse or lover has a secret to tell them that can only be revealed in front of a million peole on TV, and they never assume it's going to be something that will shock, disgust or anger them. Especially when anyone else with half a human brain can tell just by looking what the secret is e.g., they are not the gender their spouse/lover thinks they are.
Maury: Ohhh, Maury.
Basically like Jerry but instead they would often try and get the guests to come clean with a secret they're hiding instead of them just confessing, although it's usually like pulling teeth. The guests suspected of cheating, 99% of which are guys, who never seem to know what normally happens: they are put in a room with a "sexy decoy" where they are secretly being watched. And they "nearly" always start flirting with her.
Wife Swap: The two wives who have very different and conflicting lifestyles don't seem to know at all before agreeing to switch places. For example the wife who is very strict with her kids will discover that the other wife's kids are allowed to do whatever, the wife who makes her husband do all the housework and cooking will end up in the house of the wife whose husband is a male chauvinist who believes a woman's place is in the home. And instead of just putting up with it for a couple of weeks they change the rules to that of their own household.
