Both parties the player and the casino can agree to do a mediation through third-party/parties. but do you think it has bad consequences if the third party proves the player is right in establishing his identity, then the casino's KYC is not reliable?
This actually looks strange when there are sites that reject KYC because almost many casino sites that encourage users to do KYC thoroughly. Although some people or I personally consider KYC something that is not needed because considering it can leak our identity, but when there is a casino site that has a reputation and many users who reject KYC actually need to be questioned, it could be a mistake in filling in personal data so The site refused and did not finish KYC perfectly.
Until now I have never been involved in a big victory in gambling so that I have never felt rejected and also never did KYC on any casino site, because at this time I only play gambling with small bets that are not so routine. So that the KYC rejection case I have never faced and felt for now and there was also no reference regarding the issue.
You are on the safe side if you're playing with a small amount because you are not on the money laundering radar, but you can never be so sure even if you're playing a small amount but if you are suspected of violation of their terms they can ask you for KYC, KYC when you sign up to a casino that asks for KYC expect it even if you think you're playing safe or you are not betting a large amount.
I don't want to be specific on KYC issues but there are instances in the scam section where both parties have to ask third parties to interfere with KYC issues, we may question the casino for declining but a third party will validate or decline the documents of the player, for a player they have to waived and agreed to the results and both parties should trust the third party verifier.