Hi, I'm curious about precisely what risk passenger planes who do not file their flight plans will face.
My admittedly limited understanding of passenger planes makes me feel that the risk is small. Here's my reasoning.
1. Commercial flights should have their transponder on, identifying themselves. It kind of functions as an IFF. So theoretically a Japan Airlines plane can safely fly through and still be clearly identified.
2. If for some reason identification via transponder isn't sufficient and the aircraft cannot be contacted via radio, PLAAF can scramble jets to visually identify the commercial aircraft. They can then escort the commercial jets out of the ADIZ.
3. Chinese intelligence should be able to gather flight data from a plethora of online sources, figuring out where and when each aircraft will enter/exit the zone. Flightradar24.net will help anyone with a good internet connection track most aircraft live.
One thing to remember is that this is an ADIZ. Unlike Gaddafi's Line of Death, you won't get indiscriminately shot down if you enter the Zone. Submitting a flight plan shouldn't affect the risk a commercial jet faces - all it does is make it easier for the Chinese to identify aircraft in the ADIZ since they know when to expect what aircraft to be entering and exiting the zone.
On a side note,
P-8 Poseidons are to be deployed to Okinawa. Please check out The Aviationist - I can't post links...yet...