I wonder if it has to do with the perception of danger (and reality in the US with the massive human trafficking). Along the lines of "if my child ever disappears without a trace, maybe tracking will be able to locate them or where they were heading"?
I don't have children, but I would think that they would much prefer freedom with less curfews, less interrogation if they get home late, and a return to "just let your kids go out and play for the whole day" like was common 20+ years ago?
Maybe that would require trust that the parents wouldn't track their every move though... Then again, normalizing mentally accepting having your location tracked all the time is very dangerous...
Nvm, I realized after I typed this that it is only really useful for pre-teens teenagers, not people over 18.