great idea...I wonder if a 3rd party app could enable this or if that type of access is currently closely held? I'd only consider software that has super low level hardware access so you could basically control electrical access to that part of the phone's circuitry (so backdoor features can't be built that make sneaky connections).

The closest thing I've seen was an opensource app called SnoopSnitch, but it requires root on the phone and supposedly only works on Qualcomm modems.