a) You can tell if someone has turned off their location on their iPhone by heading into the Find My App, and then selecting the "People" tab to see a list of all your friends who are signed into the app. If you do not see their name or profile picture on the list, this means they have turned off their location. b) Another way of knowing if they’ve turned off their location is by looking at the Find My App Map to see if their avatar head is visible. If it’s not there, they may have turned off their location.  c) If you see a “location not available” message appear underneath the person’s name on the Find My App, then they may have disabled their location services, or are having network issues.