Well I will throw this out there. Thursday we were flying from HKG to Hano late morningi. While in HK airspace a ANA cargo flight reported a TCAS contact 3 miles, at 8 o clock, 1,000 feet below. HK atc called in the blind to the "unidentified" a/c, whih was squawking 1400 to initially identify itself, and when that did not work, to press ident, to which she got a "reply". She was able to verify their level. This went on till we transfered to Sanya, but the ANA guys were able to see the a/c and it was clearly "shadowing" them. I know the Chinese and Americans have being shadow boxing in the region of late, but this is the first time I have heard of a civilian a/c being caught up... At the time it was unnerving. Now,.... Just saying...