Originally Posted by coolcoil

I wonder what would happen if he ran into IRROPS that required an overnight stay at the connecting airport? With no card, I would think no hotel, and probably not even with a card at that age.

I do think that a mature 15 y.o. can travel by themselves just fine in most circumstances, but I would be concerned about problems that minors cannot resolve because of age restrictions, no matter how mature they are.