Around here it is legal to warm up or just idle the engine as long as the doors are locked (requires two keys. etc).
Is it illegal to leave front doors unlocked at night too?
A couple years ago, our neighbor was warming up her car and ran back into the house for something. When she returned to the car a couple minutes later, her purse was gone.
Poor people just got hit by burglars, too, a few weeks back. Entered through a skylight into the second story master BR. Crooks saw a burglar alarm control panel in the MBR and also saw that it was armed, so they stayed in the MBR. No motion detector in the MBR and I guess no glass-break sensors either on the second floor. They lost a lot.