I don’t know who they are but I know from experience what they were doing. However, when we taught our kids, we didn’t have helmets and we did it in the street or on a sidewalk. I also remember my Dad doing it with me when I was seven years old. It was a 24″ bike–no training wheels. Once, when riding unassisted, I passed too close to a parked car. I let go of the bars and put my hands out to protect myself. I crashed. I would crash perhaps a hundred more times in the next decade but I had a lot of fun. And the crashes–they were just something to brag about.