I've heard various ideas such as limiting it only after mods have expended their points (this will require implementing a cooldown to prevent a user from getting points again too soon). I want to hear your feedback, and I'll roll together something for the next major update of the site. Leave your comments
Looking at Comments.pm, that is indeed the case, but its such a minor edge case I suspect it was completely overlooked as the other site hides karma values (I incidentally found that this code is in the public release of slashcode. Incidentally, I found this code in our tree, and will post the cheatsheet of what karma values on the other site mean in raw numerical terms).