But the question remains, why do you need to know where they are? Is it concern for their safety, is it concern that they are doing something you may not approve of?

I'm fairly old so my experience of tracking kids is limited but I am really intrigued as to why we are now so concerned about having 100% visibility of what our kids are doing.

The flip side of this questions is how often do kids who are being tracked in this way either have problems that the tracking helps resolve, or deliberately work around the tracking so that they can do something their parents may not approve of?