Being that using bitcoins is actually illegal in china, its a valid concern.

Proof?

it's been discussed on other parts of the forum. Also easily searchable on the internet.

http://blogs.wsj.com/chinarealtime/2009/06/29/china-cracks-down-on-virtual-currency-for-real/

I don't think its enforced much. But hey its china who knows what they can do overnight. People forget its not a democracy.

https://www.btcchina.com/ still seems to be in operation.

Yep, not really enforced. But hey if they wanted to make example out of someone.. i can see why they are trying to be secretive.