I think that people should be able to detract karma away from other people for doing something offending. by this i mean a sort of in-between punishment for being offending, in between not doing anything and getting a warning. the system would work like this;
member 1 posts offending comment
member 2 clicks negative karma and specifies reason.
nothing happens.
member 3 reads offending comment, clicks negative karma and specifies reason
nothing happens
member 4 reads offending comment, clicks negative karma and specifies reason
administrator verifies comment.
administrator decides if comment is offending.
if offending, administrator removes one karma from person.
with this system, the administrators are only alerted after 3 people complain about the same topic, guaranteeing that the comment must be offensive enough for three people to be offended, but that there is still some way to reprimand people who detract from the forum community without breaking any rules.