They often have a card to use in their TOS, maybe stating they have right to change their TOS at anytime or some might state when they can request KYC from customer, which some may even say at anytime but if the customer do not go through it carefully, they won't see this and miss out thinking the casino is fully non-kyc.
Which is illegal anyhow, Casinos could write whatever they want in the ToS that doesn't mean a thing in court.
They could for example, add that in case of multiple winnings, they will only pay in cash at their home office, so if you win over 10k, you need to fly to Curacao, would that be legal just because they wrote it in their ToS?

Yea it also depends on what the court accept but is this not depending on the region where the casino is registered?
There are schemes which they may be able to pull off under some regions which will be favorable to them and in other regions not going to go pretty well in their favor. Some go for every means to earn profit finding loophole and other means to get customers money acting shady/scamming to them.