According to the AP report:
Google says that will prevent the company from remembering where you’ve been. Google’s support page on the subject states: “You can turn off Location History at any time. With Location History off, the places you go are no longer stored.”
That isn’t true. Even with Location History paused, some Google apps automatically store time-stamped location data without asking.
For example, Google stores a snapshot of where you are when you merely open its Maps app. Automatic daily weather updates on Android phones pinpoint roughly where you are. And some searches that have nothing to do with location, like “chocolate chip cookies,” or “kids science kits,” pinpoint your precise latitude and longitude — accurate to the square foot — and save it to your Google account.
The issue directly affects around two billion people using Google's Android operating software and iPhone users relying on Google maps or a simple search.
Among the computer science researchers at Princeton conducting the tests is Jonathan Mayer, who told the AP, “If you’re going to allow users to turn off something called ‘Location History,’ then all the places where you maintain location history should be turned off,” and added, “That seems like a pretty straightforward position to have.”