They started by sending private snapchat messages to our family. My wife screenshotted the cute baby picture, google uploaded it automatically to their backup/photo storage.
Game over.
Heck, walk into walmart, your face and your family are all scanned and added into their security database.
Its a fools errand.
I can think of few uses for privacy, overthrowing a government, embarrassing fetish, a medical illness that would cause people to treat you differently, yet none of those are showing your kids being kids online.