This post made me laugh so much, that I had to log in and reply.
You had to have played multiple rounds with the hacker in order to get banned. There are no longer any human GMs, which means it's all moderated by a computer. Being in a lobby will not get you banned, because that's not how the flagging system works. Readying up, entering the sector, and then completing a level below a certain time threshold will, however.
Enjoy the game, hopefully this time fairly.