As far as casino games, you might find yourself in this situation with a half-decent poker hand or if you're counting cards in blackjack. Casinos don't hand out advantages over the house, which is why the former is coming from other players and the latter is against the rules. As the sibling comment notes, it is generally irrational to participate in casino games and the simulator is correct to tell you not to do so.

This comes up more when you have (or at least believe you have) information that the counterparty doesn't have.