Knowing it would have a great deal of American users and that it would have to abide to rules, Mt.Gox overlooked this. Everything that followed only validated my decision to stay away.
US law is pretty clear on the fact that Mt. Gox is a money transmitter because Gox did, in fact, transmit money (that is, it had USD denominated accounts for users and distributed funds to other people from those accounts to other people at the direction of the account holder.)
> (you don't have to actually transmit money to be one, just things equivalent to money).
That might be true, but its irrelevant, as Gox (and any other exchange that exchanges a commodity for money, whether or not the commodity itself is also money) actually transmitted money, not merely "things equivalent to money".
If you're worried about what the courts have to say about the subject, it isn't debatable in the slightest. They're the ones who get to decide what the rules are, period.
If you don't care what a jurisdiction's courts have to say about the rules governing financial services, you really have absolutely no business offering financial services in that jurisdiction.