One day he won't be so lucky. Or, he will be finishing up and his phone will ring and he will answer it as he reaches for the pump handle and it will be enough to spark and then he will make the news...
There has never been a documented case of a cell phone causing an explosion at a service station. The myth of “static electricity discharge” is absolute hogwash. The origin of the ban was due to paying attention, not a safety concern over combustion.
As for the vehicle to be running as a safety concern, it too is based more in myth than practical reality. Static discharge from a vehicle is super unlikely as even now, EPA controls have fuel vapor recovery nozzles. And even if your vehicle did discharge, the percentage of air/fuel vapor by volume would need to be so high that in an open air environment, it’s implausible. For Pete’s sake, while you are refilling, cars pull up, pull off, and drive by all damn day. Where’s the difference?
Now, I’m with you, Prokop, the sign says, “Turn of motor while fueling”. So abide the law or receive an arse-chewing. But he wasn’t endangering you in actual fact.