Even if the child would be booked by mistake as an adult, it should make no difference. AC was in possession of the kid's date of birth, as this is a part of the info that has to be entered into the system during check in. So it may seem that the DOB is not checked when the decision is made on who's going on STBY. And it should be checked, because the adult category starts in AC's booking system at 16 years of age, but leaving a 16 YO behind in the worst case scenario is problematic.