For most casino workers it is impossible for them to stay away from gambling because they are in that environment where people gamble constantly. It takes a lot of self control to work in such places everyday and not be a gambler especially when you are seeing people getting lucky and making profit from it.
I read a comment somewhere before, I think the person is a casino worker like a dealer and they see a lot of gamblers lost every single day on their workplace. They can only felt sorry for them deep inside but they can not confront them directly. It is either against the law of their job or it can affect them once these people obey their tip and won't come back on the casino again. But I think there is one that is brave enough to tell the winner quietly to quit now or else the winnings will only get returned in the machine. There are still people that makes profit but their numbers are so low and then they are not usually the same people who win last time.
If we think our working environment affects us negatively, then it is better to just resign on it but some are only worried that what if they can not get hired immediately on the other company? So they just take the courage to continue. Some can also stay because they genuinely like it i.e. they are into gambling and then they can also get tip from the winners.