SXB:
What you are citing is, of course, the cautionary approach.
The problem is that you can never prove that something, anything, is 100% safe or immune from failure. It's the same as Chief Medical Officers and cellular phones/WiFi in schools. Because he cannot give a 100% assurance (in the scientific sense) that little Johnny or Jill won't be affected by a few milliwatts of RF, he opts to say "might be best avoided" or some such. And promptly scares the willies out of a whole bunch of people who are not scientists and don't understand the context.
Thus it is with phones and aircraft.
Having said all of this, I, for one, am quite happy to sit there, glass of wine in hand, fat, dumb and happy, with everybody's damn phone firmly off.
derekl