How? I don't think there's any way a phone could know if someone has a spectrum analyzer looking at it's antennas, so it wouldn't be able to distinguish between a user enabling airplane mode because they want to vs. someone testing it.
Or do what VW did and detect the testing station, I am sure the locations of the FCC test facilities are widely known.
That would still be catastrophic for people trying to avoid tracking in demonstrations for example.
Or what am I missing?
Plenty of VM evasion stuff has been caught in the wild so it would up the game regardless, which is all you can really hope for against hackers and malicious parties. They almost always go for the easy targets who don't think of this stuff anyway.
Good point none-the-less.