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
If you allow both posting and moderating, please implement some way to "flag" abuses in a future metamoderation function. Even max-karma users should be oversighted.