I let mine idle 5 minutes. I'm not going to cook the turbo bearings, an coke the oil passages for some political agenda.
The new diesels are supposedly so clean you can breathe the exhaust also.
If it is cold or thee air is running because it is ungodly hot I'm not shutting off the gen either.
Diesel does not explode or vaporize easily, and there are no sparks if someone is spewing gas all over the ground. In that case we will move fast.
Stores with fuel pumps, got a better insurance rate than other businesses, because of the safety hardware etc and their record of fewer fires. And people idled their cars and trucks all the time at the pumps. In the sixties and seventies when air conditioning became more wide spread in vehicles no one cut them off while the Attendant filled the tank, washed the windshield. They wanted the oil checked they did.
This whole thing is about establishing control over society.
Smoking a cigarette over a gas tank is stupid though running or not.