I can not believe all the banter about whether its is acceptable or not to leave a helicopter running unattended without a qualified person at the controls. I have personally had to run out on to the ramp and shut down 2 machines over the years that were shuffling along the ramp with no one on board while the pilot(s) was on the phone or he had forgotten the JLB.
I also know of a long ranger(engine running) that slid down a mountain side while the pilot landed for a leak, and another time the pilot got out of a running helicopter and walked into the main rotor while on uneven ground. So if you dumb enough to walk away from your helicopter with the engine running, your dumb enough to get killed.