[jacquesm]

It's the casino here that's cheating, and the casino that doesn't know its own business well enough to spot the flaws that are exposed. Winners have no obligation to explain how they won just as the casino isn't going to tell the losers to stop losing.

[listenallyall]

And in this case, without proof, the winners did get paid. The police and internal investigation did not result in any definitive proof, thus the seizure of funds was unjustified and soon released.

As far as protecting casino revenue, casinos have a complicated arrangement with governments but in most jurisdictions the reason they are legal is to pay hefty taxes on gaming revenue (also normal income tax, separately). Thus the police are, when investigating similar claims, protecting government revenue. The casino is just the conduit to generating that revenue.