This thread engages at least two different aircraft-related issues:
a) In an era of ubiquitous cellphones and various other portable electonics that can transmit complex powerful signals in and around aircraft, a high degree of RF-resistance & microwave toughness should be considered in the design specs and the maintenance standards for every component on passenger aircraft.
The standards should apply not only to the obvious resonant interference with nav/comm systems, but also particularly to sensors and control actuators throughout the aircraft, and also the connected wiring + innards of analog and digital control circuits and computers. Virtually everything electrical, in sum.
Goal: Properly designed and maintained passenger aircraft should be immune to the effects of cellphones and other (out of band) onboard RF sources across the entire spectrum.
b) Even when and if the standards of a) are uniformly and stringently effected, some RF-introduced random problems with avionics, controls, and systems will continue to occur, just as mechanical problems do. Many will be for the same reasons: vibration and corrosion effects can gradually unmake the high-quality electical joints and seals needed for robust RF insensitivity.
Given that a) isn't going to completely happen for some while, and b) is going to continue happening forever, limits on use of inflight cellphones continue to be reasonable.
However, the appropriate post-incident response to suspected cellphone-type systems malfunction incidents should be a full writeup and aggressive troubleshooting to find, repair, and document the faulty subsystem. One may think of the troublesome phones as canaries for fundamental problems that require repair in any case.