I can accept there are good reasons why in some situations
One pilot I wouldn't endorse was the NZ one who left a Squirrel rotors running at ground idle while he disembarked his passengers (at an airport on S. Island). The aircraft was on the grass by an unlocked gate, about ten yards from a public viewing area next to the carpark.
I was amazed to watch him walk off carrying a suitcase, through the carpark into the terminal building. He didn't reappear for well over 10 minutes. I was tempted to go and pull the fuel shutoff because if something had gone wrong, the flying debris would have been a public danger. Eventually I got my son to video it because I thought it might be useful to the BOI!
