Note: users with enough karma (like myself) can click "vouch" on flagged posts. My guess is if enough users do this, that will unkill it (like it did now).
What's that karma threshhold, if you know offhand?
Must be quite a bit. I have 3700+ and still can't vouch.
GP only has around 2000 karma, so assuming he's not mistaken about being able to vouch, maybe you haven't been in a situation where vouching was necessary?