Arbitrage betting is forbiden on casinos, they consider it as an abuse, and I don’t know how but they will know if you are doing it with multiple casinos, so, users must be careful about this linda of practices because just as op mention they will close your account and keep your money of you they it.
I also wonder how they manage to know one is using multiple casinos in order to do arbitrage, it has always been a question without resolution to me.
Either casinos talk to one another in order to prevent abuse or major casinos use some sophisticated software to perform chain analysis on the withdrawal of our money and compare of our crypto addresses also interact with addresses which are known to be under the control of other casinos. In the similar manner the addresses of exchanges are sell known and are even tagged on the most popular block explorers.
Regardless of what they do, they fact they reserve the right to confiscate your funds if you are caught doing arbitrage would be enough to make anyone reluctant of trying to take advtange of the differences of odds in several casinos.