Fast forward to a couple of weeks ago.
An adult I know was riding his bike on a country road, rounded a corner, and smashed head-on into a truck. He wasn't wearing a helmet. Fortunately he wasn't killed, but he certainly could have been.
Once I was waiting to be seen in a hospital emergency room. Another patient was a pretty young woman who had been riding a motorcycle off-road when she spun out and rolled in some gravel She was wearing nothing but a string bikini and helmet and her entire body looked like raw hamburger. She was in extreme pain and her body was probably scarred for life. But her face, which had been protected by the helmet, was okay.
Please, please, please be sure your kids always wear helmets when biking, riding scooters, skateboards, etc. And, grown-ups, please do the same. Helmets may feel hot or uncomfortable and some people think they don't look cool, but they can save your life. Nobody is invulnerable.