every promotion carried out by gambling sites has a large enough abuse loophole and it's not just 1 or 2 gambling sites that have experienced this. it's difficult for gambling sites to prevent this, especially those that don't require KYC, the gap for abuse is getting bigger, the problem is that gambling sites that require KYC will be deserted because people prefer non-KYC. the conclusion is that no one is to blame!!
So that is the reason why gambling as a whole bears a lot of risk. Not only for the gamblers but also for the one implementing the gambling activities. They will do anything to their power to get more users on their website. Bonuses and other stuff like that are always subject for abuse. Because people always finds a way how to get everything for free while monetising at the same time.