I can test my hypothesis, you know. With a script that will randomly be first to upvote and downvote comments at random. Willing to make any bet that the final score (say, five days after) won't be affected by more than 1 vote point?

[I probably shouldn't discuss the experiment here, but i kind of doubt you guys can precisely neutralize that kind of bias other than by hiding the vote from yourself before voting. You'll either strongly under-compensate or overcompensate]