"Its only a nav issue. There is no technical reason for not useing a cell phone in an aircraft, on the ground, in the situation described. End of story."
I have to agree with the previous four posters...
Even faulty aircraft inflight entertainment systems can cause flap warning messages on some aircraft (and they are designed to cause minimal interference). I've also seen my (company approved) walkie talkie opening and closing the pressurization outflow valves.
With aircraft departing.... If the mobile phone-using, Gameboy-playing, laptop-using pax want to wait even longer on the ground whilst the engineers perform maintenance tests on systems affected by mobiles, fine, but otherwise...
In the case of an aircraft taxying to the gate, the mobile phone users may not be inconvenienced, but the airline staff and the pax going out on the next flight may be.
Rgds.
Q.
P.S. I suspect the phones would be transmitting at their highest power levels in an aircraft, due to the metal fuselage shielding the signals. The pax may be frying their brains as well as inconveniencing themselves and others (but that's another contentious issue
).