That's true and part of the reason designing for aerospace applications is tricky.
That sort of thing is also one of the legitimate reasons the FAA can have for not adopting an NTSB recommendation. Requiring a seat for small children is one of those calculations. The FAA ran the numbers and assumed some portion of those parents wouldn't fly and of that portion some would drive. Some portion of flights are for physical or emotional health that would not be handled (you can calculate the increase in suicides from things like missing a loved one's dying moments). And of course driving is way way more lethal. So you have to weigh the deaths from not flying plus deaths from driving against deaths avoided if lap children were prohibited.
That sort of thing is also one of the legitimate reasons the FAA can have for not adopting an NTSB recommendation. Requiring a seat for small children is one of those calculations. The FAA ran the numbers and assumed some portion of those parents wouldn't fly and of that portion some would drive. Some portion of flights are for physical or emotional health that would not be handled (you can calculate the increase in suicides from things like missing a loved one's dying moments). And of course driving is way way more lethal. So you have to weigh the deaths from not flying plus deaths from driving against deaths avoided if lap children were prohibited.