I don’t think any registered casino platform would hide their policies from users, however, if they should ask for KYC Which was not originally part of their policies, then I think you should just go ahead to provide them with the details they’re requesting for.
There are things to take into account before we confirm a casino to be a scam and one of such things is demanding for KYC when it is not properly included in their T&C that it will become a requirement, and also if the user already passed the KYC verification process but still denied access to their withdrawals, this and many more are the most reason why some players accuse casinos of being a scam and aside from that, any other restriction may be because of the player's inability to properly read the rule and conditions of the casino.
Because a reputable casino will give you a certain bonus and includes their terms and conditions, particularly for that specific bonus, so we need to read a lot about casinos' various conditions at whatever point in time.