My 65 Dart 4 dr allows the doors to be locked without a key by:
0.) Lock passenger side doors from inside
1.) Close driver front door & open driver rear door
2.) Press inside lock down on front door when reaching from the rear door opening
3.) Press down driver rear door lock before closing rear driver door
4.) Close rear door & your locked out of the car....especially if you left your only set of keys inside the car.
I use this method to cut down on key & key lock wear but only after verifying the key is in my pocket....this practice might be important to those using their car as a daily driver.....for me it's a minimum of locking up twice a day.
