+1. In my opinion, the Chinese government has effective control over the price of bitcoins right now. Obviously they can't dictate the price but, if they decide to restrict bitcoin trading, the price would plunge.
China has implemented capital controls to prevent individuals from moving large amounts of wealth out of China. See http://www.globalpost.com/dispatch/news/regions/asia-pacific... for some background (or just do a Google search for china capital controls).
A Chinese citizen could conceivably bypass those controls by (1) depositing renminbi (i.e. CNY) into a BitChina account, (2) buying bitcoins, (3) transfering them to a non-Chinese exchange (e.g. MtGox, BTC-e, BitStamp), where they (4) sell them for USD.