Another note: people here seem to advocate buying Magic: the Gathering BTC for the eventual re-opening of withdrawals. However, with the exchange locked down the total amount of BTC and $$$ are fixed. No closed-system transaction can change any of that; for every buyer there's a seller of equal magnitude in both directions. Only the exchange rate (i.e. notional value) changes.
So in this case, we can assume there's a BTC shortfall, meaning someone won't get their BTC out. We don't yet know if there's been a shortfall of $$$ as well, but less likely unless Magic: the Gathering has been really naughty. Hence, the rational thing to do is be positioned in $$$ so as not to be caught last one on the ship. In fact, the drop in BTC price on Magic: the Gathering is the opposite of what Karpeles would want if he were trying to make right by everyone.. ideally he'd want the maximum $ value for selling an existing stake of BTC so that he could go out and buy BTC elsewhere and bring back to Magic: the Gathering to fill the hole.
1. "So in this case, we can assume there's a BTC shortfall, meaning
someone won't get their BTC out. We don't yet know if there's been a shortfall of $$$ as well, but less likely" -> It doesnt change anything. If MtGox goes under, people who are owed money by MtGox, may it be USD, CAD, EUR, JPY, or even bitcoins, will be reimbursed proportionnaly to their debt.
2. By acting like fools, the price of BTC has fell very low on their market. They can simply buy BTC on their own market at a very reduced price. They are exchanging BTC IOUs to USD IOUs. But if the hypothesis that they are short on BTC but hve enough fiat is true, then they are very happy with that change; if they "buyback" enough btc, then they will reduce their BTC debt below ther BTC assets, while not increasing their USD debt over their USD assets.
3. Even better, if they open withdrawals again someday, the price of BTC will rise dramatically. They can now sell (on their own market) some of the BTC they bought during the crisis, at a massive profit.
4. Contrarely of what has been said, fiat withdrawals work on MtGox. Delays for USD are terrible, so thats why people say that withdrawls are effectively blocked, but it has been my understanding that withdrawing JPY and EUR is ok.