Heathrow Harry: that is not so. The risk is small (actually vanishingly small) but it is there. There have been ignitions on retail forecourts. Commercially available Mobile phones are not intrinsically safe and non "Ex" devices are banned in refineries and terminal process areas.
Those (real) explosions have been with PETROL - not Jet-A1 (or diesel.) Igniting ambient temperature Jet A-1 is actually very difficult, as anyone who has done the triennial fire fighting drills will know (as you will too, I assume.)