But have all the adults in every picture you see in the media, famous or not, given consent. What about the photographs of children suffering in Gaza, or indeed in any war zone. Have their parents given consent?
It seems to me, within limits that all this fuzzing of childrens faces is a vanity, 'aren't I famous' affectation by media celebrities. If you do not want your children in the papers, then do not take them places where they will be photographed, or else control the release of their images to keep unapproved photos out of the media, as the Prince and Princess of Wales do.
Anyway, if you aim to keep your family private, and jsut the occasional photo leaks out. Who is going to remember what a child looks like. They change so fast and who a child's parents are will be known to their school friends, teachers, other people from the gardener to the Prime delivery driver.