Yeah, that is the key really, self control.
The casino will try everything they can to keep the big winners inside the casino to keep them playing more, with free drinks and food, because they know that eventually the gambler will lose all the wins they had.
It's up to the gambler to step up and leave.
Casinos know that if big winners stay in their place while enjoying lots of freebies it can keep them coming back to gambling. They will forget to immediately go home because they are still interested in continuing to gamble.
That's why casinos still host them and expect those big winners to stay where they are. And the crowds in the casino can attract their interest in gambling again. But if the gambler has strong self-control, he will not be tempted by the freebies given by the casino and will still leave the casino to go home.