My account randomly got flagged just a few days ago for no apparent reason, so now I've got to wait to be verified before I can withdraw any bitcoins or do anything except trade. Fun. Anyway, when I first got into the queue my number was precisely 14500, as I recall, though I don't have a screenshot.
Sounds like MtGox was in fact running fractional reserve, their safety margins are running out and so they're using this new technique to limit outflows.
Pretty bad in a Stock Generation sort of way.