Your scenario is highly unlikely. First of all, find my face is opt-in, so person 'C' and person 'D' would have had to explicitly opt-in for this to happen. S

Your scenario is highly unlikely. First of all, find my face is opt-in, so person 'C' and person 'D' would have had to explicitly opt-in for this to happen. Second you can control who can tag you in pictures - so person 'C' and person 'D' would have the opportunity to review the tagged photos before the tags become public. Third - Find My Face won't create tags automatically. When person 'A' uploads the picture, Find My Face will look for faces in the photo and if it finds a person who has opted in to the feature it will suggest that the person be tagged. So person 'A' will see a prompt of the form 'Is this a picture of <person C>'? Most likely person A's response will be 'I have no idea' and they won't create the tag in the first place. This is especially true since tagging someone in a photo automatically shares the photo with them.