how do you know about all these information? i play on primedice before and i saw a guy withdrawal so many bitcoins and he can withdrawal easily without problem and kyc. i think gambling site use kyc only for a player that had a suspicious activity on their account and for withdrawal a big money like 50 btc and more.
Why will the casino require KYC on withdrawal of 50btc or more ? For sure, anyone has one this much amount and he therefore initiated the withdrawal.
If the KYC is to prevent the hacking, then it is useless because hacker can withdrawal all the money even without KYC if the site is compromised.