This blog by Jeff seems to talk about such users, though I wonder whether it has been implemented in SE. Here's an excerpt:
But in the absence of some system of law, the tiny minority of users out to do harm – intentionally or not – eventually drive out all the civil community members, leaving behind a lawless, chaotic badland.
Our method of dealing with disruptive or destructive community members is simple: their accounts are placed in timed suspension. Initial suspension periods range from 1 to 7 days, and increase exponentially with each subsequent suspension. We prefer the term "timed suspension" to "ban" to emphasize that we do want users to come back to their accounts, if they can learn to refrain from engaging in those disruptive or problematic behaviors. It's not so much a punishment as a time for the user to cool down and reflect on the nature of their participation in our community. (Well, at least in theory.)
Timed suspension works, but much like democracy itself, it is a highly imperfect, noisy system. The transparency provides ample evidence that moderators aren't secretly whisking people away in the middle of the night. But it can also be a bit too … entertaining for some members of the community, leading to hours and hours of meta-discussion about who is suspended, why they are suspended, whether it was fair, what the evidence is, how we are censoring people, and on and on and on. While a certain amount of introspection is important and necessary, it can also become a substitute for getting stuff done. This might naturally lead one to wonder – what if we could suspend problematic users without anyone knowing they had been suspended?
I'm wondering whether it would work here or not - Mods(since being in public beta, I don't think any of the normal users are mods anymore) should act on this...