Again, Life360. Not only can you see exactly where they are at any given moment, but you can see the history of their movements for the prior several days. I know when they leave the house, how long it took them to get to work, when they went to the store, etc.
It’s free app available for Android and iPhones. No parent should be without it.
It can mean the difference between life and death.
These tracking plans are great. They aren’t turned on and off, though. All cell phones can be tracked. You pay a fee and you are allowed access.