I downvote here and there when I notice it, but I haven't bothered to setup any automation yet. I think the automation to crush the rewards isn't a bad idea. It might not have any effect on the spam, but at least it'll stop him from getting rewarded for his abuse. I don't want to waste all my downvote power on one spammer. I think this idea of having an account dedicated to this spammer is a good way of doing it.