This has been one of the reason why we keep seeing many casino users coming to the forum to complain about how they were treated unfair and banned for no reason after completing KYC verification.
Many users might think that the complete KYC verification is to ensure that the identity of the players are known so they do go as far as cheating or engaging in activities that is against the casino policies. Boom!...casino team ask for verification....boom! you were banned for breaking the casino terms and condition(probably multi accounting) without showing any proof can be annoyin atimes.
Casinos have enough evidence of user violations against their business' ToS but they have to be careful when collecting proofs before banning a user or refuse a banned user'a ban appeal. Asking for KYC is like an extra proof that casino wants to have before making their final decision, and I think it is a possible reason they ask KYC.
Users who violated ToS, did not know that they can not beat a casino after their cheating activities were detected and collected by the casino. Whatever thing they do next will not help them proving that they have never broken any rules there.
They can complain why a casino intended to ban my account but still want me doing KYC and eventually, it's a ban too. The casino has terms in ToS about KYC and they can ask KYC any time.