"Never"

Leave your unattended vehicle running!

"Leaving a POV or GOV running unattended will result in vehicle impoundment."

If you find a vehicle running unattended notify Security immediately at 243-2300 on a land line or 046-816-2300 from a cell phone.

Leaving your vehicle running to keep it cool or warm is not authorized.

Leaving a motor vehicle running unattended is like leaving a loaded weapon.

wth? have they truly nothing better to worry about?

Seriously, I'm trying to figure this out. I've been driving for many decades, and never heard that running a car unattended is dangerous.  Thinking I might have missed something, I googled it.  The top 3 results said don't leave the vehicle running attended.

  - The first one said cuz it causes air & noise pollution.

  - The second one said "when a child under 6 is in the car."

  - The third one said "Because it invites auto theft."

None of them played the "loaded gun" card.  Truthfully, I can buy any of the 3 above reasons although if the rationale is reason #1, then I'd also say don't leave the Admiral's/Commander's car running with the duty driver waiting because it still leads to noise & air pollution even with the driver in the car.  And we've never seen that, have we?