Earlier quoted context omitted.
I'd like to wear helmet as a passenger as well as a driver on such bike. The helmet doesn't add almost any inconvenience, is reasonably cheap and light. Why not wear it? I use shared bikes one-way quite often and I usually carry my helmet around, strapped to a backpack. In colder weather I would cycle in a business shirt. No issue with a helmet.
> Why not wear it? Car drivers often get head and brain injuries if they are involved in a collision with another car or with a tree/building. Do you wear a helmet when you drive? The helmet doesn't add almost any inconvenience, is reasonably cheap and light, as you say. Unless you're on a racetrack or driving a test vehicle, probably not.
In Europe most people didn't even wear helmets when they went skiing (on-piste) until a few years ago. Now pretty much everyone does, but it's one more thing you'll carry with you everywhere you go. And on warm days I sometimes have to take my helmet off in the gondola because it gets very warm.