I'm part way through setting up a first laptop for a child (Preschooler) but currently deciding on either a local PC account or MS family child account.

My main concern with a MS child account is not locking out the future so if by the time they are x age they can play (Xbox/MS Store) an older age rated game if an adult (Family Group) approves it. 
An extreme example would be allowing a 16yr old to play an R18 game (GTA etc).

Does anyone have any experience with doing/allowing similar.
MS has an article Grant an exception to your child’s content limits on Xbox One but its not clear on how this operates in practice.  Eg does it apply to movies/apps only or games as well.