It wasn't agasint the law for me to be in Camden New Jersey at 0100 by taking a wrong bridge out of Philly, but common sense told me that a white boy driving a VW in Camden at night should turn around ASAP and get the heck out of dodge. I came to this conclusion by only looking at the area I was driving in.
The key word is common sense.
In my driveway around my house, doors to car would be unlocked. Given my driveway and house being off the road, I even leave my keys in the ignition running at times. However, common sense tells me NEVER to leave the keys in the ingition without myself in the car, law or no law outside my home. That same common sense would tell me if I lived in a more surbuban area, not to leave the keys in my car even in front of my house.