We only talk about legal casinos and only about legal methods of punishment. Naturally, they will hand over the violator of the law to law enforcement agencies
They can't arrest anyone
And thus they can't "hand over" anyone either. If they try to pull off that thing, they may end up a violator even if the fact of the collusion gets confirmed in the court. So, as long as we are talking about legal methods, all they can do is call the cops. And this is what happens when you call the cops in America
I don't know how it works in America. In my country, if you see a crime committed, you call the cops
This is likely the best course of action in almost any circumstances
You never know what's actually going on in a situation that you are a casual witness of. The point is, you may end up involved in the crime if you try to take justice into your own hands as had been the case with your example until you changed your stance. So if you call the cops and they do nothing, it is their problem from now on. If you don't, you may become complicit through negligence, i.e. not reporting