Well, since U.S is the number one aggressor and warmonger on Earth, it is in China's best interest to
place those sensors anywhere it deems necessary in order to maintain some vigilance against the US.
Remember, the U.S shot down a Syrian plane inside Syria 'self-defence'... what sheer hypocrisy. The US uses 'international rule of law' according to its wishes, China needn't listen to these Western hypocrites.China should use every means available to her to defend herself, and keep building her arsenal.