I'm not sure. This is my third user account. Coming from reddit and slashdot, I had an abrasive posting style, which sometimes would generate hundreds of upmods for my posts, and sometimes would generate dozens of downmods.
Maybe this is purely me, but having a month or two of my posts going down the black hole 1. saved people from my vitriol and 2. forced me to think about why it happend.
Now, I think there are too many people that will downmod a comment because they disagree with it, or because it responds to one of their comments in an unflattering (but appropriately toned) way. If this happens to you early on you get put in the kill list.
You also get kill-listed if you upmod a killed account too much, which is to prevent shill accounts I suppose.
The real way to tell, however, is that whenever you are logged in every page view takes 10 seconds or more to load.
Overall I think that all these shinanigans are pretty effective at knocking down the number of people who are just angry and bringing that anger to the site. They might be perfectly smart people, but there are plenty of smart people in the world, and people coming here to rage are such a huge negative that it is best if they are eliminated from the site, even if there are occationally people who get kill-listed 'unfairly'.
This is a BBS, not a criminal court. If you feel it is unwarranted you are banned from posting to a Bulletin board, my suggestion at that point would be to create another account and proceed rocking out from there. If you can't get over the injustice of being slighted by an automated system on a discussion board, then your priorities are incredibly retarded, and probably you should reflect on your life and figure out why? I should say that this isn't meant to be directed at anyone in particular, except maybe to me circa 2006.