Roadtrip:
This incident happened almost 3 months ago and If the Chinese what to make an issue of it they would've done it at that time. What happened was that the story was first leaked out by western diplomats to the media and THEN the Chinese 'unoffically' commented. China and the US have NEVER made any offical comments.
Also I wouldn't be too surprised if the presidental plane of Japan and Taiwan (Both Boeings) were bugged by the US. It's a routine procedure that the public (And us) should not be taken too seriously.