Vortex - Sure. It happens to us all.
Some months ago, during taxi to stand at LHR, I heard (from the row behind me) the distinctive 'Tick-Tick-Tick' that an Ericsson makes as it registers (I am a long term Ericsson user).
I turned to look trhough the gap in the seats and glared at the bloke and told him to turn it off. He looked VERY surprised. However, I doubt that he aceeded to my request.
You may be able to comment on another point in this debate. An ex-colleague of mine worked on software developemnt of the Airbus 321. He said that their concern was not the odd phone or two but the problem of numerous phones.
They were concerned that, if multiple phones are turned on durings (say, finals or taxi to stand) they would all be registering at about the same time. The combined transmissions to multiple networks - perhaps greater if foreign mobiles are trying to locate suitable network for the first time - would provide a far greater interferance
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