Sarah Connor usually doesn't mind that her mom, more than 1,000 miles away in Gaithersburg, Md., can follow her every move.

The exception? When the smartphone app that plots Connor's location on a digital map betrays her on the occasional Monday morning.

"She can tell whenever I happen to sleep through my 8 a.m. class," said Connor, 20, a junior at the University of Minnesota.

The app they both use, Life360, shows their locations on a map 24/7, as long as no one hits "Pause." They see it as a safety measure, a little digital peace of mind. Yet mom Lori Connor admits it's tempting to peek, especially on Monday mornings.

"I do call her on it sometimes," Lori Connor said, laughing. "That's when she'll say, 'Mom, stop tracking me.' "

Amid a national debate about online tracking and National Security Agency spying, millions of people like the Connors are choosing to track each other on a more personal level. Using smartphone apps and GPS technology makes it easy to share individuals' locations with a limited circle of relatives and friends. Parents track children. Adult children keep tabs on elderly parents. If the family dog has a propensity to run, why not stick a GPS tag on his collar, too?

Such easily accessible surveillance technology raises all kinds of questions about privacy in a digital era. It makes perfect, practical sense to some — and can be lifesaving when used to find people with dementia who are prone to wander. Others are appalled at the thought of making their location constantly available, even to a loved one.

"You get dramatically different points of view from people about how private they consider their location," said William McGeveran, a law professor at the University of Minnesota. "So much of it is contextual. People who would be happy to have locations tracked within their family would be creeped out if they realized that Google was doing it. Other people have the reverse feeling."

Crossing the 'geofence'

GPS technology isn't new. But more than half of American adults now own smartphones, which can easily be used as personal tracking devices. The usage can range from basic (friends as moving dots on a digital map) to seemingly Orwellian (subscription service mSpy monitors the location of a smartphone and use of the device).

Apple offers the Find My iPhone feature to help people find their misplaced devices. Using the same technology, it offers the Find My Friends app to help people find their iPhone-toting friends.

Major telecommunication companies, such as Verizon and AT&T, also offer different options for tracking others by smartphone or with gadgets. Want to know where the kids are? Stick a sensor in their backpacks that triggers automatic text messages to Mom and Dad when the kids cross a digital boundary, known as a "geofence," set up around home or school.

Even the dog can't escape this kind of surveillance.

Amanda Zweerink of Richfield outfitted her pitbull, Cooper, with a GPS collar after his fourth escape. Now all she has to do is check a smartphone app called Tagg to see where he is. "We use Tagg for peace of mind," she said.

While it's hard to argue against tracking lost pets, it's harder to convince people that they should share their whereabouts.

Chris Hulls, co-founder and CEO of Life360, which claims 30 million families use the app, said it took a while for the app to catch on because the idea of tracking — a term he dislikes — turned people off.

"With any new technology, there's this moment of hesitation where your mind instantly goes to the worst possible use," said Hulls, who pitches the app as a communication tool. "Once people use it, their perceptions really change."

McGeveran, who teaches about privacy law at the U, said laws around GPS surveillance haven't evolved as fast as technology.

"There's a lot of legal loopholes around location tracking," he said.

As for people's willingness to track family members and friends, McGeveran said: "Creepiness is about expectations."

People who are used to going about their day without someone knowing where they are at all times are likely to balk at sharing their movements, he said. Those most willing to opt in are generally younger people who have grown up with social media and location-sharing apps, as well as curious tech enthusiasts.

Practical allure

Jack Butler, 25, of Bloomington, started using Find My Friends a couple of years ago as a novelty. He shares his location with about 10 friends, and it's useful when they are trying to meet up, especially at big public events like the recent Red Bull Crashed Ice in St. Paul.

But it's not for everybody, and even Butler turns it off sometimes.

"I remember mentioning it to some friends, but they were like 'Not a chance,' " he said. "They either like it or think it's bizarre."

One area where tracking technologies have been embraced is in caring for adults with Alzheimer's disease and dementia. Wearable GPS gadgets and smartphone apps can relieve stress on caregivers and make it easier to find someone who gets lost, said Debbie Richman, director of education and outreach at the Alzheimer's Association of Minnesota and North Dakota.

"That type of technology allows somebody with dementia to be safe and yet be monitored and then maintain independence, which is really great," she said. "I see it getting more and more mainstream, where it's going to be a more accepted intervention."

Dick Wagner and his wife, Carol, of Mound, have been using their iPhones to cope with his Alzheimer's disease. When Dick Wagner goes for walks — something he loves to do — Carol Wagner uses the Find My iPhone feature to track him along the way, just in case he gets disoriented.

It's not an invasion of privacy, but a way to maintain his independence. "I know that Carol can see me at any time, which is really helpful," he said.

It may not work forever, but for now Carol Wagner said, it's a perfect solution.

"If his phone is in his pocket and turned on, I can find him," she said.

Katie Humphrey • 612-673-4758