"relatives don't share pictures of our kids' faces" - serious question: why ? I have seen that from friends too, and I respect it - but I don't understand what bad outcome that prevents.
Additionally, pedophiles and creeps do actually exist.
I love that I get this question all the time, when from where I sit, the question should be to all the other parents: "Why do you insist on posting your children and their entire lives on social media?"
It's something you can't ever get back once its out there, and we all know Facebook is perfectly happy selling out user's pictures as training data for AI companies.