The only reasons I can think of for getting banned are spamming or multiple accounts. I've heard of developers getting their applications booted, but I've never heard of someone getting banned themselves! Probably the worst site to get banned from (besides Hacker News, that is!).
I have one FB account. I have an open dev account and an empty application.
I got an official Facebook warning about one year ago for creating a group "For every 100 people that join this group Apple will donate a laptop to a needy child." I think it got to 250 people in an hour and then it was gone.
I had a middle name listed on Facebook as "rupertmurdochsucks" which was kind of a running joke. The only thing I can think of is that I recently contacted support about a bug that switched my class year to "Alum." They told me how to fix it and I did. But the CS person reported me for having a fake name, which seems really stupid, especially because they won't tell me what is going on. I also had a group that promoted Kratom, which probably goes against the facebook Terms of Use but the group co-admin didn't get banned and the group is still there.
:) tell me about it... I actually got banned from Digg twice (first time for being a member of a pay-to-digg site, second time for submitting my "adult" site multiple times. The same NSFW site on reddit got me modded up.)