That would still contradict anonymity though. They can't track users by IP address or cookies (if Tor browser is used... it is transient for the session) and ha

That would still contradict anonymity though. They can't track users by IP address or cookies (if Tor browser is used... it is transient for the session) and having people register means they are likely have to come out of anonymity. If they do manage to register one from anonymous throwaway address, then it essentially make paywall moot...