Totally understand, and I booked a flight without showing any frustration towards the check in desk because I know they were just following the rules implemented by the airline
Couple of side notes too. A while back I posted about elite visa for parents only and allowing the kids to overstay. I imagine this would also be applicable for that scenario.
Also, it’s worth nothing that you can’t book a flight for young children without including at least one adult. So we had to book a flight for 3 people, but cancelled at the point we received a booking reference and all was good.