This is a problem that I often encounter with gamblers. As an example: https://bitcointalk.org/index.php?topic=5221321.msg54134740#msg54134740
Instead of implementing KYC at the beginning of registration due to account ownership policies, casino owners prohibit multiple accounts and place these conditions far in the Terms & Conditions page that is usually missed by new users. (maybe in the last 3/4 pages).

It's better to avoid casinos that have this kind of policy, every time you are registered as a newuser, your are potentially suspected of being a second account etc. even though you are not. So they will freeze your assets and they will no longer trust your KYC so will not be enough to close the case.