[Ninian Dryhope]

"If the brakes were faulty, how is that the rider/buyer's fault?"

That is a big IF. What are the chances that both the front and back brakes on a bike are both going to go from working well to not working at all? It is not going to happen since there are simple, independent, systems, that do not suddenly fail. They may work suboptimally, but they would still stop the bike. It is far more likely that the kid was not paying attention to what he was doing and rode out in front of a car, as kids are wont to do.

[mlc9852]

Sounds like you're guessing.