I could probably go one better. I was joined a phone forum as I was planning on flashing a new ROM and was asking a question before I did it.
I got banned for 30 days for and I quote "Improper punctuation, Read forum rules". I read through my post and I did make a mistake. I put a comma where there should have been a full stop but common it was a bloody typo

I am also joined a few car sites and one had a big blow up there about 2 years ago. A member got a month ban or something for constantly breaking the rules but it would be something silly like the odd curse word by accident during a heated discussion but nothing like an insult or anything just something like for f*ck sake. He got banned anyway which started people asking where is he gone because the discussion was continuing without him. The forum found out he was banned which sparked people saying it wasn't fair and that it wasn't fair leaving the discussion open and the guy couldn't defend himself or something. I think if I remember correctly the discussion was on something to do with some work he wasn't happy with from a forum partner and the partner kept deleting his posts to hide the work so the banned guy brought it up like most people would.
Once people asked what happen "x" they started getting banned just for asking reason was something like trying to start an argument or something. Needless to say loads of people got banned either permanently or temporarily over a paid forum trader who wanted to hide the fact he messed up and he got the mods on his side.