But is that because you do not want/care that they know, or because you want them to NOT know? Our family is not required by any means to actively inform each other about our movements, but at the same time they're no secret. I don't even check Apple's tracking app daily but when I need it, it is so convenient. "Hey, I'll come pick you up in 20; I see you're at the park. Just check on me and I'll pass by to pick you up."

The typical example when we use it is when one person is somewhere and another person is driving and will do a quick road-side pickup while passing by. Don't want to stand outside in the sleet for ten minutes waiting for the family member who is delayed due to weather? You could call every other minute and distract them, or you just check where they are right then.