I'm a lucky person overall, so can't speak too much to IRROPS, but I have routinely booked myself and my kids on separate bookings, dating back to when Unaccompanied Minor service would've been required if they were truly alone, and "Linking" the reservations has always been sufficient for customer service to see both and do any necessary adjustments for the entire party. Never once was there an issue that the kids seemed alone when they could not be.

This frequently involves us being in different cabins, so I think I'd have heard about it if there were any doubt they were actually accompanied. (I did sit with them almost all the time before middle school, but, by the time the kids hit puberty, they'd rather sit many rows away from a parent anyway.)

In my case, my spouse won't use status nearly as much as my kid will. (DH hates to travel, though he's invited all over the world because of his work.) So sometimes it the kid should earn miles and the adult should be the companion.

But it was not uncommon that one kid's schedule would change, or the other would visit Grandma a little longer and then fly home with her... From my point of view, you can trust the linking of reservations