Third-party lockable gas caps become popular back then to prevent people from siphoning the precious fuel from your car. A local newspaper columnist (
Herb Caen) reported a story about how a driver violated social etiquette by cutting in front of all the other cars queued up for their turn at the gas pump. The driver ignored protestations from all those already in line, so one of them took matters into his own hands. He removed the lockable gas cap from his own car, walked up to the other car, placed his cap on the other car, locked it, walked over to the curb, and dropped the key down the storm drain. A chorus of cheers ensued from those in line.
I don't know if this incident actually occurred or not (since Caen took submissions of local-interest stories from the public), but it was a feel-good story at the time when people were frustrated with the "gas crisis" and tempers flared over the misbehavior of who felt more entitled than others in the same situation.