That aside, parents who use location tracking to try to catch misbehaving teenagers ought to weigh the harm they feel they are preventing against the harm such surveillance may do to their relationship with their child. When done collaboratively, however, location tracking can contribute to adolescent safety.

For example, parents might come to an agreement with their young driver that they will check her location if she’s running late, rather than texting or calling her if she’s likely to be behind the wheel. And Mr. Curtis has told his own children, with whom he does use location tracking apps, that if they ever have an urgent need to be picked up they, “don’t have to even call,” but can send him a text reading 911 — the agreed-upon family code — and he’ll be on his way.

In a similar vein, John Shoemaker, a 16-year-old who lives in Coronado, Calif., suffers from a severe nut allergy. He carries an EpiPen and an inhaler, but has a plan with his parents that they are to find him by his iPhone if he doesn’t check in or respond as expected. “I see it as a safety net,” he explained. “If something were to happen, it’s nice to know that somebody would have the capability to know where I am.”

Appreciate the Limitations of Location Tracking

Parents who know where their teenagers are should not make assumptions about what they are doing. I’ve cared for an adolescent in my practice who got in trouble with her folks for swinging by a banned home to help a friend retrieve a lost item. And I’ve known teenagers who were doing all the wrong things, in the exact place where they were supposed to be. When it comes to knowing what is going on with a teenager, having their location cannot take the place of having a sturdy, working relationship.

Treat It as Temporary

For many families, an adolescent’s wish for increased autonomy outpaces the parents’ readiness to grant it. At these times, location tracking can be used to establish trust that leads to greater freedom. Parents might help their tween or teenager move toward independence by saying, “We expect you to tell us where you’ll be, to let us know if your plans change and to respond if we reach out. We’ll confirm your location by phone for a while, but once we feel that you’re on top of things, we’ll stop looking over your shoulder.”

Tracking can also be used to rebuild trust that has been broken. After their teenage son drank himself into the emergency room, a family in my practice grounded the boy for two months, then tracked his location — with his full agreement — for several weekends until they felt they could, again, count on their son to look after himself.

And though teenagers and young adults routinely location-track their friends, parents should not assume that they enjoy an open-ended tracking arrangement. It’s one thing for your roommate to know that you are spending the night at your girlfriend’s dorm and quite another for your dad to have that same information.