I admit I did a couple revenge tks or played around with some trolls in the past. It sucks not being able to crush those guys' heads, but in the end admins shouldn't have to think for ages before banning someone who's causing trouble. It was ok during the beta because most of the professional trolls were known (and in some cases, tolerated), but now it's clearly impossible to make a difference between the one who started and the one who's trying to defend himself.
There are no real solutions. If you come across someone who's really, really annoying, you can always use screens or fraps. Usually a banpoll works if you don't rage and explain what's happening.