Posts that are already at -1 shouldn't be able to be modded down.
Yet users such as SCO$699FeeTroll - http://slashdot.org/~SCO%
24699FeeTroll - which already post at -1 have their posts modded
down. Sometimes there are multiple moderations down on posts that
were already at -1. There are already significant restrictions on users
who post at -1 automatically, but this results in them being unfairly
banned from posting.