Anonymous wrote:A lot of people here are really bad at risk assessment and/or math. A really small risk (head injury while riding a bicycle) doubled (by not wearing a helmet) is still really small. Plus, as some have mentioned, most of us grew up never wearing helmets. Head injuries are bad, of course, but this particular case (riding without a helmet once) is pretty low on the list of risks that are worth worrying about.
It may be a small risk, but it's potentially catastrophic consequences. That changes the equation.
For me, I'd say no, and the result of not getting to go to his friend's house after school would mean he'd be more likely not to forget next time. (A helmet doesn't seem like an easy thing to forget before you leave the house -- if you always wear a helmet, wouldn't you notice right away when you get on the bike that it feels different, wind on your hair, etc.? If he forgot to take it but realized shortly after getting on his bike, he could have turned right around and gone back for it.)