“Their identification code is what helps to distinguish them on remote sensors,” wrote Valencia. “When China spots a spy plane, its military assets probably go silent. But with a ‘false flag’, the spy plane may deceive them into continuing activity and communications can be monitored. Under international norms, civilian aircraft should not be shot. The US may be betting on this, ironically taking advantage of China’s adherence to international norms.”
https://nationalinterest.org/blog/reboot/why-does-china-think-american-military-planes-have-been-spying-them-176909
123 not it!