The biggest weakness is a full blown raid of their office.
Or legal complications involving their new US presence or other draconian threats that would lead to accounts being limited or frozen. I'm not much of a conspiracy theorist, but there is plenty of evidence on these forums of "special" cases where people have found their funds suddenly unavailable, especially at the Paypal of Bitcoin, MtGox. The excuse for which is irrelevant imo, but is usually under the blanket guise of "AML compliance". So you can't process a transfer to the bank? Fine, send the funds back to the owner then.
If you value your bitcoins, treat it like you would gold. Stop lending in USD, stop gambling it away, stop investing. Bitcoin *is* the investment vehicle so long as the price is so volatile (it will settle one day, and then investment again might make sense) and unless I'm mistaken, there are no insured exchanges nor exchanges that are willing to go to jail to keep their customers happy in any situation.
