one of the nice things about bitcointalk is that many of the scam websites are exposed here so people can protect themselves as well
some sites also publish they methods and you can verify that their lotto and other games are provably fair
But in the aspect of gambling, I doubt if any scam site has ever been exposed without them first scamming a member of this forum off his or her money, we get to know that a site is a scam only when a member comes complaining about the situation, this is why I always advice people to always watch it very carefully while they are testing out a new gambling site, if the money is important to loose, then don't risk it, allow others to rest and come back with their review before you make your own decision.
well, the site can only be a scam if it scams someone.
the point I don't get is why these people don't just go the right way and be fair/don't scam
in the long run they'll make much more money than scamming and being exposed for their faults