I actually do want a feature where I will get a notification on my phone if someone nearby has snagged a picture of me or my kids. A creepy shopper at Costco once took a pic of my 2-year-old. They pretended to be working up a conversation with my little kid meanwhile they had their phone at hip-level to snag a shot. I even confronted them about it. The Costco employees couldn't do a thing. Phones with cameras are useful but have also become a nuisance.

Edit: It makes sense that such a notification system would be impossible to implement. Perhaps, registered offenders should not only have their location placed on a map but their phones have certain privileges disabled or monitored.