As far as I know, one can earn the Peer Pressure and Disciplined badges by deleting and subsequently undeleting posts with the appropriate scores (-3 and +3, respectively). See: I cheated on the Disciplined badge, how bad is it? and Badges should reward positive behavior
I guess most people don't care enough about these badges to actually use this kind of exploit, though.
Question: What proportion of Peer-Pressure and Disciplined-badge-earning posts stay deleted?
Since it involves deleted posts, I don't think it's possible to whip up a Data Explorer query to answer this. Perhaps there's another way to give an estimation. (My mistake.)
It seems totally possible to do this in Data Explorer, although my Data-Explorer-fu is not up to scratch.