DDoS the whole infrastructure. They have done that to GitHub before by hijacking traffic to Baidu. With millions of phones in the US under their control it’s fairly easy to overwhelm any website (Mercedes comes to mind in recent news) they don’t like or even cripple the whole national wireless network.
Also even if you are not of direct interest to China, what about your friends and colleagues? They can use you as a tool to get to those that you have direct communication with.
Also even if you are not of direct interest to China, what about your friends and colleagues? They can use you as a tool to get to those that you have direct communication with.