...looks like they did know just before the announcement... the owners of those large Bitstamp bids are guilty of inside trading!!!
Maybe they had their withdrawals pending and watched their receiving addresses. As soon as one tx came finally through they put in the orders.
Nope...read the anouncement - they've got a fix and it will be tested and implemented soon.
Definitely insider trading by some individuals at Bitstamp - it went on well before they posted the anouncement.