There is not even a minimum deposit for availing of that promo. It is basically free money. I wagered $60 (requirement to get $15) with like $1 (even less than that). I can see that they have many more similar promos that guarantee even higher rewards for wagering a certain amount. I can't try that as it requires a certain VIP level (like 10k wagered or so). So, you are right in assuming that there will be more bonus abusers and in order to maintain fairness  KYC can be requested for suspicious activity. I personally never got that from the casino in question but if I solely play to abuse bonuses, I am confident that I will get a KYC request.