I agree that the quizzes with stupid questions like "what is the first letter of the alphabet - a) A, b) zebra, c) soup" appear to have no skill whatsoever and ought to come under lottery rules on that basis.
http://veroblog.wordpress.com/2007/06/26/endemols-cheetah-found-to-be-a-cheater/
The get-out normally employed is the same one as on everyday product competitions (like on bags of crisps etc) which state "no purchase necessary". Somewhere in the tiny print on screen they say you can also give your answer online. This is while you listne to the on-screen muppet repeat the number to cal for the bazillionth time with no mention of this free option.
I have always cynically assumed that these online answers are simply ignored. I'm no longer sure that is a cynical viewpoint. (Although it is said that 'a cynic is one who sees the world as it really is, rather than belives it to be as it ought').
There are investigations underway to determine if this 'free' option is sufficiently well promoted, and if it still leaves issues such as time contraints for answers to be submitted. In particular there are questions being raised about the fact that very simply not everyone has access to the internet, free or otherwise, and that in fact the divide between the internet haves and have-nots closely mirrors the pattern of people who watch this kind of stuff.