As for your other question, KYC is not required for playing and registering, however it is a MUST if you withdraw funds. If you attempt to withdraw without being verified, you will be notified about it.
I believe this is a bad idea. This will lead to some users having their assets confiscated if they do not wish to go through KYC.
If KYC is mandatory for everyone, then you should require it from the beginning. Before the user makes a mistake and deposits money to your casino. Otherwise, you deceive players into thinking they can play anonymously, but in reality you are preventing them from making withdrawals without providing their personal information.
The same thought came to my mind first. My guess is that such a solution was adopted in order not to scare new players away with the KYC requirement, but surely many of them will feel cheated. To avoid problems, you should either make this requirement for everyone or at least make it very clear to everyone who registers.