People have been accusing MtGox of being insolvent for years and the malleability stuff has been going on for weeks. Plenty of time to whip up some damage control.

That is an interesting point. How long would it actually take to coordinate between those exchanges though? Its been a big day in BTC news and I'm sure everyone with some skin in the game is watching the news like a hawk.

Probably not very long. But I'd wager they've known since at least this morning. Given last night's resignation of Mt. Gox from the Foundation, I'd say since last night.