You have to do 'mug bets' to avoid getting gubbed. The decent sites like profit accumulator show you how to do those.
I've been gubbed on one website. That means no more bonuses there for me. However I did one offer and I mug bet because I've heard they are over zealous. Didn't stop them getting rid of me. But it's only Betbright so not a great loss.
What happens with some people is like anything. They get bored. They lose motivation. They send their bank roll on an emergency or something frivolous. It happens. You can always buid back up slowly if you want to. If you don't the you've made a few grand easily. Good if you're wanting something fixed at home, a holiday or to pay some debts x