If the child stopped breathing because the pilot was drunk and the plane slammed into a mountain, I would agree that the airline should have been more careful. If the child stop breathing because he was exposed to peanuts on the airplane, I would say that the mother should have been more careful. She is responsible for protecting the child from peanuts, not American Airlines.
I would predict that the probability of the airplane slamming into a mountain is greater than a child dropping dead from breathing a molecule of peanut air.