Ok... #7 is almost always enforced except in extreme cases. And most are explained if you find the right thread. I'm not about to explain why any unbanning occured, because you'd have to talk to the person who did the unbanning (as I'm not a mod) to get the knowhow into it.
Offhand I can think of three reinstatement cases I've either heard of or seen
Johnson
Banned for: Dunno
Reinstated because: Dunno this either
Banky
Banned for: Not sure exactly, though I imagine it's not hard to guess why
Reinstated because: Supposedly "saved the board" (though the veracity of this is disputable to some)
Sakura
Banned for: Wishing death on Damaramu
Reinstated because: On-the-record is because she supposedly didn't know it was against the rules and shouldn't have been banned for it. Off-the-record belief among some is because she's friends with Dames.
Not exactly exceptional cases, as far as I can see, but that's just my opinion
RoyalBlue:
Banned for: being a PBP
Reinstated for: not being a PBP
Also, IIRC Banky was banned because Marney picked out something he'[d said about looking to get a reaction out of people when he posts, which is against the rules.