Upvote:7
In France, the PARAFE system is open to people aged 12 or more when arriving in France but you have to be over 18 when departing. This fact suggests several things to me:
In many countries, the rules around that are a little more complicated than βchildren over 14 can travel unaccompaniedβ, which is probably why they are directed to a regular passport kiosk. Interaction with border guards can be an occasion to check whether a child is actually traveling alone or with an adult.