I think you are right about the retrospect aspect. No one who thought they had detected a pattern (which wasn't later confirmed in the news) would then offer to return the money because they cheated. So I suppose my comment that the gamblers were cheating once they detected the pattern is only really valid in retrospect.

That said, I still don't think I could keep the winnings knowing, in retrospect, that I had won them unfairly, but I think you are right about the casinos needing to sometimes suck it up and take a loss if that's the game they're going to play.