@CommonBoy yes it would be theft. Say the cheater won a game, gets an amount of money put onto their card (card details would obviously need to be given as part of registering for the site). Then the cheater gets found out. I can't see how the site could gain access to the player's card LAWFULLY in order to take back the money. What would you do about false positives? "Oh sorry, we took your money because we thought you were a cheater.". That would kill the site.
And BTW this IS advertising, even if it isn't your site.
And BTW this IS advertising, even if it isn't your site.