WOW! Simply, wow! It looks to me that if some regulatory body choose to do so, they can walk into any banking institute and demand to see the records of (I will use this example) Intersango. They can simply claim that a certain client of theirs with such-and-such Bitcoin address conducted some illegal transaction and that an investigation is warranted. This account is now closed until we finish our investigation. This could take a week. After a week goes by, they return with another concern of another address and the whole process starts anew, thus freezing the account indefinitely. Furthermore, during the interim, Intersango will not be allowed to open up another bank account in that country, and if incorporated there and choosing to open a bank account in some other country, their incorporation privileges will be revoked. I sure the hell would hate to be such a company in their shoes if such an event did occur.
~Bruno~
Sort of. When the DoJ went after the online gambling providers, they went after the payment processors. People's money was tied up for ages because the gambling providers didn't have enough reserves on hand to directly pay out people's balances (at least one of them had been co-mingling funds, but that's another story) - the money was in the bank accounts of the payment processors and those were frozen. While many users did receive their deposits back, it demonstrated the extent to which payment processors are a weak link in the chain.
While it's possible that a regulator might choose to go after one particular exchange, it's just as likely that they'd do what they did with the online gambling drama and go after everyone at once. There's no question that a sub-set of customers on every exchange are going to be using the exchange to launder money, evade taxes or commit other financial offences. The offshore poker providers weren't actually breaking any laws in the jurisdictions in which they were licensed. It pretty much came down to the DoJ having the power to disrupt their business indefinitely if they didn't play ball. The Bitcoin exchanges are tiny compared to the online poker providers and its unlikely they'd win in a showdown with the US DoJ.
Loup is right that there are a number of US agencies which could really fuck up an exchange's shit pretty much regardless of where that exchange is located. I just believe that once that particular can of worms is opened they are more likely to go after everyone than after just one exchange.
I'm not sure what the fines are for failure to comply with AML/KYC requirements in the US. Here in Australia, the fine for either not reporting a transaction as required or reporting it late is up to $1.1 million for an individual and up to $22 million for a company. A single transaction could have multiple reporting requirements attached to it, so you can get hit with more than one fine for a single transaction. Big banks might be able to absorb those kinds of fines, but I doubt there's a Bitcoin exchange on the planet which can afford them at this time.