I would be a lot more strict with temporary cool-off bans, but I would not perma-ban anyone except in very extreme occasions - personal threats, revealing personal information, stuff that does tangible harm and does not only hurt people's pride. But the cool-off box? Ohhhh, that would be constantly at capacity, I can tell you that.
Why I'd opt to keep the rude people around and bring upon myself the fate of having constantly watch and re-temporary-ban them, you ask?
Why, because the place would get fucking boring if all that's left was a bunch of yes-men talking about weather and watering pot plants.