I have taken an interest in this thread but I dont really see where it is going.
Is the use of mobile 'phones specifically banned on private flights? Well, if it says so in the legislation it is, but no one has yet come forward with a reference.
Is there any evidence mobile 'phones interfere with instruments? This from Boeing would suggest they dont.
Boeing performed extensive tests as reported in AeroMagazine's Interference from Electronic Devices in response to reports by flight crews of anomalies that they believed to be caused by electronic devices. The flight crews had apparently confirmed the effect by switching the "suspect" device on and off and watching the effects. Despite this, and despite the fact that Boeing in many cases was able to purchase the actual offending device from the passenger and use it in extensive testing, Boeing was never able to reproduce any of the anomalies.
In any event in light aviation a great many flights will not be navigating by reference to radio nav. equipment so the issue is redundant.
Could the use of a phone be distracting? Clearly it might, depending on the circumstances, which is why their use in cars has been banned. If it distracts you from any of the tasks involved in operating the aircraft clearly whatever the legislation says or doesnt say you would be nuts to use a 'phone in flight.
That is about it, isnt it?
Not much point in a load of posturing.