From my anecdotal source, I've been banned a few times, and only once was it justified. The other times, the mods not only could not tell me what rule I violated, but resorted to insults just for my asking. There's entire subreddits dedicated to this type of piss-poor and outright abusive behavior from the mods. I'd wager that, from the perspective of the average user, the mods are the "bunch of children and adults acting like children". To me, they're like the DMV or TSA - small people who "volunteer" just for a small amount of power to make themselves feel like big people by abusing that power. Unfortunately, thus far, I have very little evidence to the contrary.