Emailing is definitely the way to go. I've emailed PG about a post that got flagged to death and he was fairly quick about unbanning it.
I don't think that link is for un-hellbanning an account. I think that's if you have a bot that messes up, or doesn't respect the rate limiting expressed in the site's robots.txt, and the IP of the bot gets blocked. If it were for un-shadowbanning, the username would be asked for rather than the IP address. Having said that, I forgot about that unban link -- thanks!
Just to confirm, you are spot on - the link has nothing to do with hellbanning. But I guess the most common cause is if you restore a browser session with lots of HN pages.
I don't think that link is for un-hellbanning an account. I think that's if you have a bot that messes up, or doesn't respect the rate limiting expressed in the site's robots.txt, and the IP of the bot gets blocked. If it were for un-shadowbanning, the username would be asked for rather than the IP address. Having said that, I forgot about that unban link -- thanks!