I think hivemind voting is pretty evident at times. You will see certain users with a much higher upvote (based on placement) than someone who had a far more insightful, far more thought and discussion provoking comment that was posted much earlier - and those certain users are people with names the community knows and respects (often rightfully so). This doesn't mean that those users should be upvoted just because of who they are.

Granted I have no facts to back this claim up - but I have seen it happen again and again - just the way certain popular blogs always reach #1 regardless of their content.