I suppose I could set up a proxy or something. And I was planning on scraping everything to a new community site anyway, so maybe I should take this as the incentive to do so.
Hacker News has an IP unpanning procedure but I don't think Arc Forum has one.
In the Arc 3.1 code there is a function `set-ip-ban` for unbanning users, but no `unban` op.
(Someone should add that to Anarki, actually.)
(def set-ip-ban (user ip yesno (o info))
(= (banned-ips* ip) (and yesno (list user (seconds) info)))