Google Maps collects a history of everywhere the user has been, and calculates the locations with several methods to make them extremely accurate.

Catching some criminals is a good thing. Ten years ago I would have said that catching a bank robber was good. Now that banks have stolen so many billions from people around the world, and the US government has let them get away with it, I hesitate to condemn someone for stealing from banks. Nonetheless, there are other crimes for which I would support catching the perpetrators.

But this method can be used for all sorts of reasons, including catching whistleblowers. It is dangerous to allow the existence of any system which tracks people's movements.