I like this idea, maybe a gambling site can implement a tool like that where you can set if how much money you will use in that session and once you drained it, you can't play anymore until the timer runs out. That is for us to prevent getting addicted but a warning or some notification like what @molsewid said is also a nice thing to add.
This is effective to some gamblers because not all gamblers are heavily addicted but they only get addicted because they forgot that they have been playing continuously, no one reminds them to take a break but I wonder why there's no gambling site that did this until now? are they afraid that their income will get lessened?
I have never seen a feature like that, however at least to me it seems that it would be even more ineffective than the current self-seclusion scheme that we have at the moment.
And the reason for this is that this will depend on people actually setting limits before the session about how much money they want to spend through it and then simply giving up if they happen to lose the money they allowed themselves during that session, so even if we ignore for time being the difficulty in coding something like that it is still does not seem as an effective measure, as those that can know how much they want to gamble beforehand and then respect that amount are people that can already control their gambling, while those that cannot do it will probably forget to set those limits at all and lose the capital they had at the casino at the time.
