Character not showing in character select screen, but still exists

Really there's no reason they can't look at a snapshot of the game on the date your UA was created (or around there - it seems like they do weekly backups), and see if you had a Cygnus then. Having a Cygnus level 100+ on the prior server check would be a decent criteria to unban them. It would be a little harder than just seeing which characters have UA skills though. And would be more a thing to do after banning everybody who created a UA without an attached Cygnus in the last 2 weeks.