How do we know if that user was really not in fault? from what the OP has explained it, the user claim tons of faucet and "bonus farming?" and smarter enough to make profit out of those free bets, that sounds like an abuse to me. Though it's not always gonna be the case, but mostly.
You talk like you have not encountered dubious casinos before. They do anything to make sure those who win will not get their winnings. It is not even about claiming tons of faucet. I have claimed on faucet sites and there were restrictions on what tokens to claim at certain duration. Some make it like five tokens daily even if there are countless of tokens there. Now tell me why a casino can not do same if it think it is going to be a crime, than allow gamblers play them and then use it against them?