Google Trusted Contacts
I am guessing that the nay sayers to this app probably don't have young children.  I have two sons (16 and 13) who are always out and about socialising with friends, or at sporting / musical activities.  My older son gigs with his band late at nights, and let me tell you - as parents, my wife and I do not rest easy until we either pick him up or he gets dropped home.<p>Any app that lets us check on our kids' whereabouts quickly and effectively without taking them out of the zone (Have you ever tried to get a teenager to call to let you know "Hey everything is OK"??) is a blessing IMO.<p>An app like this would be restricted just between my wife and I, and our two boys.  No more than that.  No more is needed.  We are an 'absolute trust' group and quite frankly, the idea that any of us would want to hide our locations from each other is simply not even a thing.