The fact is that an exchange commingling all their customers funds in one single bank account is simply non-compliant, and even illegal in most of the EU.
Just check how brokers work: you need to open a bank account UNDER YOUR NAME on a certain bank, and give the broker an authorization to operate with your account for this or that purpose - but customers funds are never commingled, each customer has his own separate bank account.
Bitcoin exchanges (apart from B-C afaik) do not operate that way (not even Kraken), exposing customers to a huge risk. It just takes one rotten seed (eg, a drug dealer) operating in exchange X and the only option LE has is to freeze the full account - that's why you cannot take customers deposits* in the EU if you are not a bank.
*deposit = holding funds on behalf of a third party - those funds are NOT legally yours, you are just holding them on behalf of your customer - that's what banks and only banks do.
So through in a gag order and this could have happened to Gox, I'm sure lots of silk road money was in Gox's bank.
I love this logic all the attacks on Bitcoin send the price up. This crap is already happened in Canada, the 5 big banks are hostile to Bitcoin, exchanges here are looking to bank overseas. Banks in jurisdictions what are friendly to Bitcoin are going to face the type of international scrutiny and resistance Mizuho Bank did in Japan for supporting MtGox.
This makes coinbase look the most viable, just not good for trading as you purchase is canceled if the trade goes against them.