It's better to call for the day and forget about it, there's always a new day and a new session that they can try it again and who knows if luck will permit they can recover it little by little.
They know how to behave when gambling. They also do not try to recover their losses due to errors in their strategy so they will just end their gambling game that day. They may not try gambling for a few days to think about other things that might be successful in the next gambling game.
I personally believe that the best thing to do in this case would be something that may end up helping everyone all the same. I know that it is not going to be that easy, and I know that stopping is the hardest part of gambling, but that's just fine, we need to just arrange something that should benefit everyone all the same. I get that it is going to be quite difficult to handle, and we need to end up with a troublesome issue if we are not careful.