[fwip]

Presumably they were worried about misclassified images, or images sent by other kids.

[themaninthedark]

The above proposed system could get ugly...

Family A enables system.

Kid B sends dick pic to Kid A.

Kid A decides to view it, Apple notifies and makes it viewable to Parents A.

Parents A are now guilty of possessing CSAM. (Distributed by Apple for extra fun)