Good point. In the case I described, someone could gain status in the community by consistently voting up good articles and voting down bad ones. This would add to the other two methods of becoming known to the community (commenting and submitting). Perhaps people who are respected would not want to risk tarnishing their image by supporting a bad article, and the support of people who would be willing to sell their 'vote' would be worthless?
As an aside, I wonder if each of article submissions, comments, and voting could be thought to respectively show that a person is interesting, intelligent, and has good judgment?