I think that AP and banning should in no way be associated, as each one serves a different purpose on Armorgames. AP would be negatively affected as it would look like some sort of rating on how good you are. I wouldn't like it.
If you get banned for spamming, you spam will be deleted. And lots of it.
If you get banned for being a flamer, then you will prolly just get banned again and again until your account gets deleted.
No points are taken away for the ban itself. If you lose points after you get banned, guess what? It is because you spammed a lot. Too bad, so sad. Your own fault.
And no, I do not think we need to bother with an AP deduction for every ban. Because, more often than not, more than one ban makes you no longer viable as a person..ermm...member. ^_^
