On any forms of business, there will always be abusers like that but business owners can do something to stop them. If it's an online casino then they can increase their website's security and they can also enforce a KYC to intimidate those who will try to abuse their sites but if ever the abusers insist to and they are caught out, it will be easier for the casino to trace them.
Some criminals will just hack someone's account that are verified already by a KYC and they will use it for their exploits. Problems like this will be solved out easily if a user who got hacked will cooperate on the casinos immediately and then the casino will freeze their accounts.
Where money is rotating, there are always a lot of people who want to steal it. In a casino, especially where there are a lot of players, there is always a lot of money. Therefore, security is of paramount importance for the casino.
Theirs no casino game that security never be the major important thing to do, for any casino to protect it's interest you most have a good security by using a KYC but most of the players doesn't like KYC verification from any of the gamblling casino platforms,