May I throw another one into the mix! I'm leaning more towards registration - yes, for kids too! Over many decades, I've picked up 2 distressed and traumatised kids off the street due to accidents. * If the helmet or bike had a registration number, parents could be notified straight away. * If I'm noticed attending to that child by latecomers, at least I can't be held responsible for causing the kid's distress whilst I've taken note of the rego# * If our dogs have chips to facilitate the location of owners, shouldn't kids be linked the same way to their parents? Only then, does it come down to the cost.