>Instead, users must verify their age using a credit card or a government-issued ID. This check must be carried out by an external service, not the porn site itself.

>This system, referred to as “double anonymity”, means the porn site receives only a yes-or-no confirmation that the user is of legal age. The age-check provider knows who the user is, but not which sites they visit.

So is there an issue here if the external service disposes of the card details immediately following confirmation? I'm not exactly sure how this would/could work though.