The other reason why some gamblers do not want to pass KYC is because people worry that it will bring bad effect especially those who live in a country where gambling is illegal.
If gambling sites were known for providing authorities with the info, that would would be a legitimate concern. But I've never heard of such cases. Was anyone ever punished in his own country because it's illegal to gamble there and a foreign gambling site were he/she registered gave that info away to their authorities?
Yet, I don't blame people for not wanting to pass KYC in those circumstances. Even though it's unlikely to get caught, it's better to avoid breaking the law.
Money can change good person to bad person especially when it comes to big amount of money so documents sales may happen in any casinos if there are some naughty staffs.
That is true, unfortunately.