First off, before I attack the idea, lets call them 'Constructive' and 'Critical' for now.
- 'Constructive' - First X downvotes
- 'Critical' - First XX downvotes
Or whatever, even if it is monthly or capped in some way, my critiques will hold the same.
The purpose of badges
The purpose of badges is to reward, encourage, or acknowledge positive behaviours or events. Some of them are in your control (Commentator) some are trusted to luck (Enlightened). But they are all designed to recognize that some desirable behaviour has occurred.
Two factors must be considered:
- Is the intended behaviour desirable?
- Is the side-effect behaviour desirable?
Is it appropriate that users downvote? Yes. Downvoting is an important if underused part of the site. So the "intended" effect of this badge must be considered to increase downvoting, and we will first grant the premise and assume that it will do that.
What are the possible effects of people doing this in good faith?
Ultimately, the two reasonable options of downvoting being overused or underused by site, I'd rather that they be underused. Being downvoted is usually a disconcerting and uncomfortable event. It is also distinctly unfriendly. I always try to leave a comment or an answer when I downvote.
However, it is a part of the site, and it is important because we want users to be able to downvote answers which are well-formed but false. If an answer is fundamentally wrong, I'll downvote them. Not enough people do that, because they are worried about being nice. But being nice and having a strongly positive community with a few cantankerous 'keep-them-in-check' annoyances is a good thing.
This means that I feel that even in the intended case, this badge would be detrimental to the community.
People "game" the badge system. They try to collect all the badges, often through whatever means necessary. This means that users would simply downvote anything they see nearby. Obviously, this is completely unhelpful, because the user will be trying to find the flaw in something which isn't flawed.
Encouraging retaliation. This one is a little unlikely, but it is possible. Basically, if you receive a badge for downvoting, it is announcing that you are someone who downvotes often. This makes it easier for people who are frustrated with downvotes to have someone to target. It is sort of like a wall-of-shame for something that isn't shameful.
Discouraging comments. Downvoting is still a little taboo. Hopefully, users who downvote explain themselves clearly and in doing so, make themselves helpful to the poster. However, once we create badges that highlight downvoting as a positive or encouraged behaviour, we aren't necessarily advocating downvoting in a responsible manner, we are supporting downvoting as an end in itself. The action and not the intent becomes the encouraged behaviour.
Obviously all three of those are pretty negative effects on the site, even though they are (as side-effects) not guarantees but rather possibilities.
In both the intended and side-effect case, I feel the results are a net negative.