Morning.
A good discussion here. I believe we've spoken about it before?
As it has been pointed out, it wouldn't work particularly well for the social elements of the site - it is the equivalent of sticking your fingers in your ears and shouting "LALALALA". And I don't think anyone is up for that.
When things get a little heated we (usually the weekend ed) will suspend a user for a cooling off period. Most will be reinstated (unless you send us snooty emails!) after a few days.
I think, for now, this is the best we've got to offer!
All the best,
Spare Ed