KYC verification at time of registration would solve such problems. But I don't think it's going to happen in crypto casinos, mainly because there aren't enough regulations in this market. People who use crypto casinos usually prefer to stay anonymous. And if one casinos would implement KYC at the time of registration, they would lose lot of potential customers. They would just move to another casino where they would be to game anonymously.
And gambling market is shady thing in general, no matter it's fiat or crypto. You can deposit large amount of money and lose it without any issues. But if you will win bigger amount of money - prepare for problems. Casino will start investigations to find that maybe you did break their TOS and prevent your from cashing out your winning. This case isn't exceptional, maybe only huge amount of money here is exceptional.