Actually this brings up a very interesting question I hadn't even considered before:
In terms of bitcoin crossing borders and for the purposes of international commerce - where is a bitcoin?
If someone in the US pays someone in thailand you would (or I would) immediately think a cross border transaction has taken place. But Bitcoins only really exist on the blockchain, right? You don't somehow store them on your own machine, only the means of accessing them (keys in your wallet). And the block chain is everywhere. A transaction is a mathematical change of ownership from one key to another, a wallet merely a collection of keys and previous transaction records (the latter probably able to be rebuilt from the blockchain anyway)...
So did any bitcoin cross a border?