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.
That's why someone needs to have a good self-control to join gambling. A gambler who has bad self-control, will be very risky because he can't stop himself when he makes a mistake. I can't imagine if a gambler ignores the reality if he gamblers excessively. He can spend all the money in a day because he can't stick with the allocation he made. I call they are weak gamblers because they have no control in gambling and he failed to deal with the ego.
This type of gamblers will be easy to have a problem with addiction and loan money. It is very possible because he will always continue to gamble until the money is over. And if it is over, he will try to get the money from other people, borrowing money will be an option to choose. Finally, this gambler will end up with addiction since he already gambles too much.
Because of this matter, it is hoped that every gambler will try to exercise themselves to have good self-control. It may be quite difficult but it is important to keep gambling in a healthy way.