I moderated one subreddit that was loved by users. It wasn't about anything that is illegal or controversial. The controversy came not from the content, but from how we were running the community -- we were breaking a reddit rule that was in place to prevent spam. I understand why they had that rule and I agree that it probably makes sense for most subreddits, but like any blanket rule: it doesn't perfectly fit every scenario. So, we had our own method of preventing spam and it worked.

The admins didn't care that we had a thriving community, no spam, and they banned the subreddit. They also blocked anyone from ever creating a replacement with the same name (still to this day). So, it definitely does happen. I'm keeping it vague here to maintain my anonymity.

Side note, reddit dropped that rule about 2 years ago so I suppose we could start one up again, but I've lost interest in that topic.