Well, in some ways it is clearly more of a political move. The Chinese want to exert more influence over the disupted territory. They thought that this ADIZ would help them do that.
But the US is not going to play along with those requirements. The ADIZ as detailed by the PRC requires that any non-regular civilian flight file a flight plan and inform the Chinese of their transponder codes and frequecies.
The US has said no in a very direct way, both verbally, and now, a day later, physically. I expect in the areas right over those Islands, where the Japanese have been administering the islands and flying their maritime patrol aircraft for over 30 years, that the Japanese will also now clearly say no.
But the fact is that the US did it first, and that was probably by desing, even though this was a planned flight. they did not cancel or alter it and used it to make thge US the one who took the lead.
This also gives the PRC a way to more gracefull back down. I expect that if the PRC now uses the ADIZ as a "buffer" zone, to identify any aircraft flying an agressive flight path aimed at the Chinese mainland, and then only intercepts those aircraft at a pre-determined distance well within the zone, that things will stay calm.
However, should the Chinese up the ante and begin deploying AWACS on each end of the Zone, with multiple flighter patrols within the zone (all of them on a 24x7) basis to try and truly enforce the whole zone...then there could be trouble. I hope that does not happen, and really do not expect it to because the cost and tempo the PRC would have to maintain to enforce such a large zone strictly at such distances from the mianland would make it pretty cost prohibitive to me. It's the kind of a thing you exert over a much weaker opponent, or in a time of war. neither of those exist in this case..
Here on SD, to avoid the otherwise likelihood of national fervor on both sides resulting in calls for enforcing the zone completely on one side, or in terms of responding with military force against the zone on the other, lets try and focus our efforts on a defensive nature of the ADIZ, and the opportunity the PRC has to avoid a direct confrontation with Japan. IOW, lets avoid talk of direct military confrontations. If the Zone becomes a buffer for true protetction of the mainland only, then there would little need for escalation.
Anyhow, that's my advise. Otherwise the forum members on both sides of this could easily work up quite the lather over it.