Btw there are some solutions for these kind of users even without withdrawing:
1. Ask to freeze their account for a while (you won't be able to unlock it even if you request).
2. Some casinos offer additional wallet where you can lock your funds.
Btw that's the personal problem that needs to be treated, it means that you are addicted to gambling and like other kind of addictions, this one can ruin your life.
This is why I was saying that casino business is a bit different because if you cannot withdraw your money right away, then you may end up gambling with it and lose it all. So in an exchange it is "I have 100 bucks in it, I withdrew all 100, they haven't sent it yet, but it is there and coming and I can't do anything with it" , whereas in a casino you could have "I withdrew 100 bucks from this casino, they didn't do it, they didn't had hot wallet so I ended up gambling with it and lost it all", it is possible and that's the problem.