I dont see any reason why would someone in clear mind share his KYC with someone else, if a person plans to gamble himself. Only a short-sighted or stupid person will allow someone to impersonate him. This refers not only to gambling. Or a person should be ready to become responsible physically and financially for the things he havent done. Those couple of dollars that people ready to receive for their identity, does not match that size of problems the could obtain.
For money. People leave on 3rd world country have no problem selling their KYC in exchange for money.
There’s a lot of people in my country that do sell their KYC through verifying someone exchange account and other services that requires KYC to unlock limits.
I believe this is the target of some user that offering this KYC buying.