I'm pretty sure China always has some sort of travel advisory on it. The current new advisory ("Reconsider travel") is due to “the arbitrary enforcement of local laws, including in relation to exit bans, and the risk of wrongful detentions.” If you still want to go, going with a company like
ABD, who will try to insulate you from such things is probably your best bet. But ABD really cannot do anything for you if the government detains you, except likely try and get you in contact with the US consulate and the people who *can* help you. Personally, given the current animosity between the US and China, I'm not sure that I'd be going until that situation has improved. While I *loved* the trip, there are so many other places to go that aren't quite so risky at the moment.
Sayhello