I've been driving since 1975, and I've done it twice. Both times were not a big deal as I simply had someone bring me my spare key.
A more interesting story was many years ago, I was walking through the parking lot of a local hospital after visiting a patient, and noticed two girls struggling to unlock their car with a wire coat hanger. They were nurses who worked at the hospital, but they had locked the keys in the car. As I walked by I asked if they needed any help and they asked if I could try to unlock the car.
I took the coat hanger, changed a couple of bends that they had started with, stuck it in the slightly open window and yanked up the door lock in under 5 seconds. I was astonished, as were the two nurses.
I simply looked at them and said "I had to work my way through University some how!" and walked away (they were too old for me to want to pursue any "reward").