My 1/50 of dollar... I hold that nodes should be voted based on thier content. If Anonymous post something informitive and insightful then ++ it. If merlyn or even vroom posts something that is flat out wrong or flaming someone -- it. Real simple.
There is more involved her than XP. Taken to the extreme personality voting can bury real useful info. Generally I don't downvote unless I am sure that the info in it is wrong.

As for this way of dealing with it.. I don't really see the point. Even if you narrow it down to whomever it is...Then what? You made the anoalogy about the vandalism the catch there is after you narrow that down you can get law enforcement to do something about it, last time i checked there was no Perlmonks Police Force. I mean the most this can do is encourage other people to begin downvoting the offenders nodes, which is exactly what you say you want to stop.

As a final point about this. The node may have gone down at first, but as i write this the rep is +17 which to me shows that the few personality voters are still offset by those of us who take a node on its own merits.