@jaro1190 private trackers need to restrict registration to avoid behaviors that damage torrent health, such as hit and run and ghost accounts, which are accounts that are abandoned shortly after being created.
this practice encourages users to maintain a good ratio, which in turn helps torrents stay alive for longer times.
another serious issue that comes with permanent open registrations is the growth of bot accounts used by DMCA agents and other bad actors to monitor torrents and scrape swarm data.