It is clear from what you say that all gamblers should have a limited amount to gamble in a casino or online. This is the frequent problem of a gambler, which is why it always leads to big losses in gambling. Those who don't know how much they will lose gambling in a casino.
I think many of them known or have an idea on how much they're going to lose but they just turn their eyes blind when they're already losing.
Ego is hard to beat and recovering is much easier to think of than accepting the big losses that someone might have.
Those that can't track their losses or don't really track at all, many gamblers do that. They're having hard time in figuring out how much budget they will do to gamble.