“Netflix would’ve avoided this controversy if it had plainly told subscribers what it was doing somewhere in the app or with a notification. Instead, people discovered that Netflix was utilizing Android’s physical activity permission, which is strange behavior from a video streaming app. In some instances, it was doing this without asking users to approve the move first, as was the case for The Next Web’s Ivan Mehta. You’ve got to be transparent if you want to monitor anyone’s movements.”

Source : Netflix explains why it snuck a physical activity tracker onto some phones – The Verge