Betting on a bad line doesn't make you a cheater. If they offer a bet on something that already happened, it's not cheating to accept it.
They aren't "catching cheaters". They are the ones cheating the players.
I read a bit about it in the meantime and it is not actually a crime. However, any bookmaker will ban your account for sure. As far as I can see, this is quite a large and well organised scam business, so now I am not surprised why so many similar complaints apper here. It's just an industry!