Royal Melbourne Children’s Hospital is an excellent hospital. I suspect they were blindsided by how the visit turned out. They might have expected the usual Royalty visit - respectful, dignified event with genuine purpose eg opening new hospital / raising awareness of childhood illness and research advancements etc.
Instead, they probably had a team from LA herding surprised patients and parents into the photoshoot zone, disappearing after a few posed photos and then finding the photos posted onto a fashion merchandising website.
There might not have been a protocol to follow, or if there had been a protocol, the LA team may have considered it optional and ignored it.