bustabit doesn't have kyc afaik i've played their a couple of times and received my withdrawals with no problem. Also I haven't heard the guys from bustabit doing any kyc to their players. They also have a dice site called bustadice I guess they also don't have any kyc there. Another gambling site I know that don't do kyc is luckyb.it there's not much users playing there because of the big minimum.
Is this something new? Because I have never heard that mentioned sites asked anyone for KYC, although it is or might be written in their TOS.
To be honest all fiat casinos are enforcing KYC and with all this regulations and buzz around crypto I think we might see KYC in every crypto site, not only casinos. It is just matter of time.
In bitsler afaik they only do kyc to their highrollers maybe the same thing goes with the other 3 casinos.