Up into the 1960's lots of cars still had the ignition lock work similarly to the doors or (separately keyed) glove box, where the locking function was optional

Up into the 1960's lots of cars still had the ignition lock work similarly to the doors or (separately keyed) glove box, where the locking function was optional. Normally you would unlock the ignition, remove the key, and then anyone could start and drive the car without needing a key. You couldn't re-lock the ignition without the key like you can a door, but there was nothing like a universal habit of locking the car doors, and automatic locks were an extreme rarity so it was very common for many drivers to go without keys most of the time, and they rarely locked themselves out. Car theft was so much less prevalent, but if you did decide to park in a questionable location it really made you think "yikes, I'm gonna need a key for this".