It's not been new users interestingly. Just people who are used to their regular high rewards, and where the downvote was an unexpected occurance.
I also find it hard to define abuse objectively. For me personally, high autovotes on daily posts already cross that line. I hope to come up with a more commonly agreed with list, but if it's based on that narrow criteria it makes more sense to find a dedicated anti-abuse team that wants to handle it and shut it down for the public.