I think is not too hard to stop when losing in gambling. But due to much addiction have make most gamblers feel that if they continue to chase after losses that they would going to recover their losses in gambling, which is coursing them to lose more money in gambling. It's essential to understand that gambling depends on luck, having a limit and self control in gambling is always necessary because it will enable you gamble freely.
If you start exerting self control from the time you're already losing considerably in gambling, is very much harder to achieve, but if you plan for that earlier by having a gambling budget and finding the casino account only with what you can afford to lose and disciplined not to find more than once, then you're on a safer side, worst case scenario you'll lose your deposits and you're fine since you'll not deposit again, but at a time you're losing and you don't have a budget and worse of it all you've funded your casino account with more than you can afford to lose or keep funding to recover losses, then you're doomed because you don't have a gambling principle and then your emotional control would be next to zero.