I'm not implying most people could do it.  But surely someone could do it, and would be doing it, you'd think.

Remember how BTC-E has always had low prices? There's a reason for that: hard to get money in.

And you know how now BTCCHINA has really high prices? There's a reason for that, too: hard to get money out.

If it was easy to do, people would already be doing it and we wouldn't see as large a gap as we do. China is a Communist country, and they have a strong hold on their currency. Just doing some quick Googling, Chinese residents can only send $50,000 per year overseas.

So, let's say you put up $45,000 to buy 150 coins. Send them to China, sell for $340 each, split the $6,000 profit with your Chinese partner, and have them wire back $48,000 (while also possibly paying taxes and bank fees, etc).

Oh, and don't forget to add in your trip to China  

So you might make $3,000 for the year. You could exceed the limit by having your Chinese contact's friends and relatives send you transfers in their names, but it seems like that would require even more trust.  And if the price of bitcoins goes way up and the price difference stays the same, you'll hit your limit earlier and make less profit.

It's a nice idea in theory, but I don't think it will pan out as well as it looks. Please let us know if you do try it, though!