A lot of people seem to have an issue understanding the subtlety of proving that something does NOT cause interference as opposed to merely lacking evidence that it DOES cause interference.

Yes, it is a very low probability for most PEDs, but not zero. I'm only aware of a couple of tests that demonstrate some interference; one with cell phones in rather high transmit power states and placed extraordinarily close to aircraft wiring; and the other in a more accidental case in a private aircraft with a rather old portable AM/FM radio (the local oscillator apparently generating harmonics interfering with the aircraft radio).

I think the issue will be a partially opening of the rules may lead to a flood-gates wide-open mentality for what is brought aboard and used on aircraft.