Guys, just leave the sovereignty issue alone. No one is going to "win" the discussion, and I think everyone here has set views that aren't going to be shifted.
Jeff & co have shown a lot of tolerance, so let's get this thread back on topic.
The fact that the US advised its own airlines to follow Chinese ADIZ rules could not be interpreted as tacit acknowledgement of legitimacy of the ADIZ. Rather, it is a necessary step to absolve the US government of any legal or moral complicity and liability in the unlikely even of a commercial airliner being lost or shot down in the said ADIZ with loss of life after failing to follow Chinese rules.
I don't think the US would do anything else with even if she was in the middle of rallying every nearby regional power to fly their military aircraft in defiance Chinese ADIZ tomorrow, which at this moment I am not sure the US is not actually doing.
The fact that Japanese government asked its own civilian airliner not to comply with Chinese ADIZ should be seen as an utterly reprehensible act, totally irresponsible with lives at best, cravenly using flying public as potential human shields at worst, that is in effect holding flying civilians of Japanese and foreign nationality hostage to score political points with Japanese domestic audience and open up maneuvering room for japan in a game of checkers against china.
One does not tell civilians to walk into some place where some one else has declared a weapon free zone, regardless of whether you think the weapon free has any legitimacy at all.
If china wanted to score points with western public opinion, china should have harped on the fact that prime minister of Japan is a loose cannon who would put the lives of westerners flying on Japanese aireline in danger just to make a point to china. But chinese government probably doesn't have the sort of sensitivity to lives and legal obligation needed to detect this opportunity.
In Beijing's place most major western government would have immediately detected the true nature of Abe's misstep in asking civilian airliners to no comply with Chinese rules, and would have capitalized on this mistake to pillory Abe as a loose cannon with a cavalier attitude towards civilian lives.