Foxcotte,
I find that hard to believe in this day & age of anyone suing anyone for anything that the airlines/aircraft companies/mobile phone makers/mobile phone operators haven't tested this extensively already
a) You are forgetting that the majority of airliners out there were designed and built before mobile phones were commonplace, so this never arose in the design specs.
b) mobile phone operators do NOT want people doing more than 120 knots trying to operate on ground-based networks with ordinary mobile handsets, the doppler effect and the cell swamping effect cause real problems, so why do tests which would encourage people to try?
c) If the airlines could enforce taking people's mobiles away from them quickly and efficiently, without massive upset, they would. But you try separating peopel from their phones and see how far you get. Alternatively, see the bear trap you open up when trying to reunite a hundred-plus 400 p*ssed-off commuters with the correct mobile phones at the end of a flight on a tight turn-around
d) it's not just the transmissions: if a phone rings, with a vibrating alert, it creates a pretty hefty magnetic field. Even on a low-tech Cherokee I've seen this affect the compass. The passenger turned off his phone pretty quickly (I should have checked more thoroughly before departure).