Choosing not to teach your child to stop immediately when you say stop can kill or seriously injure them. There is all kinds of evidence of serious injury and death of children who ignore parental warnings.
I was bringing up the rear so I could keep a watchful eye on Aaron. Part way through the ride, Aaron apparently decided he wanted to ride along the path on the other side of the sidewalk and veered off in that direction. Despite my calls for him to stop, Aaron continued on toward the path and the unprotected bulkhead. He managed to stop his bike before it went over the edge, but he went flying over the handlebars and over the edge of the bulkhead, landing face first on the boulders 6-8 feet below street level.