actually related to KYC which is enforced in casinos there are good and many benefits. but sometimes anonymous gamblers don't want to do the KYC.
it's true what you say if a casino asks its customers for KYC, it means the casino suspects suspicious activity such as money laundering or bonus abuse etc. so that the casino has full rights to ask KYC to its customers who feel there is unusual activity.
and basically, if the casino is licensed but not KYC required, it will eventually ask its customers for KYC when there is a problem or a large withdrawal. so for me when I want to bet at a licensed casino, I will do KYC earlier to avoid if there is a problem I won't be asked for KYC again.
KYC prevents fraud. If the casino suspects that a person is cheating, it forces him to undergo additional KYC procedures. If a person bought an account with KYC or fraudulently passed KYC, then he will not be able to provide supporting documents, and therefore will not be able to withdraw money. Therefore, in this case, there is no point in cheating.