You surly studied a lot on the facts, but you are thinking on the line that one event leads to another, with a set of rule, not on the line that how leaders will consider the issue. In fact you talk as if the leaders ain't present.
Thanks a lot for your detailed reply. Actually I agree with you on that China is not a country following rules. Therefore, the risk of BTCChina is not really the legal risk, but the risk of threatening the central government.
Currently, I think this risk is pretty low. First, BTC is still not well known yet. Second, the daily volume is just millions of CNY. Most importantly, now most investors are happy because of the BTC appreciation.
The risk will be larger if 1) the BTC becomes more mainstream, 2) there's a huge crash of BTC price, or 3) one of the trading platforms may finally be proven as scam and there're a lot of angry investors.