The US State Department currently has China at a Level 3 (reconsider travel) advisory level.
Summary: Reconsider travel to Mainland China due to the arbitrary enforcement of local laws, including in relation to exit bans, and the risk of wrongful detentions.
While there would be a certain “I told you so” satisfaction if anyone going to the Chengdu Worldcon lands in trouble, I’d rather forego the pleasure. If you have to go because of fannish obligations, keep your head down and concentrate on making it through.
In other news, the Chengdu Worldcon released a Hugo ballot to the Internet then pulled it.