Yep, I also think that one of the effective ways to cool down a keen gambler would be to prohibit the use of the gambling platform completely. For example, an option that, after some specific time or after a certain amount of money is lost, forcibly unlogged the gambler's account and doesn't allow re-authorization until a certain amount of time has passed.
That's one effective way to stop a player from gambling further on that day using that specific account. In such a scenario, a casino can say we did our part. We made it impossible for you to continue playing from your account by respecting the limits you placed on yourself. The player now has no case against the casino and can't claim that they were still able to play despite set limits. If the player has other accounts on the same casino or accounts on other platforms is an entirely different thing that has nothing to do with responsible gambling.