That's definitely the risk if you are using a verified account that is not yours. Your account can't be verified forever, and sometimes a casino would also require another verification as required by their regulators. That's the risk since you don't own the account information. You'll surely fail in the second verification, which means your account might get locked and your money will be lost. Hopefully, we are aware of this risk and not only think of the short-term benefits before buying this kind of offer.
I think the OP of this thread relying to casino rarely ask for second verification to account unless the current user is using different IP address that doesn’t matched to the records of the casino.
Also, The buyer can request again to the OP about another round of verification to solve the problem considering this service is honest. I’m more concern on the point brought up by other user about the potential account recovery of the OP since he is the original owner of the account using the KYC.