~snip~
If by virtue of greedy gamblers that abuse the bonuses system and a casino then decides to halt bonus offering to its customers that are due it. Such casino would only be making a bad business for themselves because it's going to drive customers away from the casino when they realise they are not getting bonuses anymore as it were even with how much they spend gambling.
Of course, a strict regulation can be helpful.
If a casino decide not to compensate her users just because some random gamblers misused the privilege for customers to earn more bonuses then I would not blame the casino for such a decision because there has been high cheating on casinos that tend to be generous by greedy one time users that are only interested in getting the bonus and less when such opportunities to cheat are not available.
Casinos need to be stricts most time and bring those greedy gamblers to book. There are still casinos that don't do enough or reward their customers enough and that alone can learn to frequent lamentation by real users.