Ahh ignorance in its true form. You can't use mobiles on the tarmac for this very reason. Why don't you try it, stand right under the wing vent as an aircraft is being refueled on a windy 40 degree day just to see what happens. Take the battery on and off until you get a small spark.
The radios have batteries too - so how do they not spark? They are just commercial Motorola units.