For valid identities, I think gambling platforms have not too strict verification steps, so if we don't want to provide real information, we can absolutely use alternative information, and in case as the OP assumes, I think things are quite comfortable when winning prizes and withdrawing money is simply a matter of providing your identity, so there's nothing to fear if that money is more important than your reputation, and in the case of people with important identities, they may not need that money.
imagine when you need to withdraw above the limit of the site when you need to go through providing your legitimacy as winner ,
why not provide this earlier?
and the problem also in some site that they are not implementing KYC in account creation and in depositing ,but they will implement when there is withdrawal ,showing that they are only trapping gamblers and take the advantage or possibilities that the said withdrawal will not go through because of questionable players.