Netflix managed to alarm some Android users who noticed that the popular streaming app was detecting their physical motion activity without explaining why. The company confirmed to The Verge that it was using this data as part of a test to determine whether it could find a way to better optimize streaming performance when customers were on the move. This could include both everyday walking around and also schedule-oriented movement like a daily commute.

The strength of your cellular data connection can often vary wildly when you’re traversing city streets or riding a bus or train. So it seems Netflix was looking into the possibility of intelligently adjusting video quality based on a user’s activity to avoid buffering or other content interruptions. Netflix has explained how it obsesses over video codec efficiency and “quality of experience” (QoE) before. In those scenario, you could imagine the app flipping into some kind of low-bandwidth mode if it detected a flurry of movement. You can already download shows and movies for offline viewing, sure, but sometimes, it’s easy to forget to do that.

Netflix says it has already concluded the test. It only ran on Android devices (even then, it was for just a select group of customers), and the company has no plans to roll out the data-gathering test more widely.

Hey @netflix why does your Android app want physical activity data? pic.twitter.com/Lv0QUL0w9g — Beto on Shrooms on Security, Shitter of Posts (@BetoOnSecurity) July 27, 2019

I think 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.

Netflix was unable to immediately answer whether it will be removing the physical activity recognition permission from its app now that the test is done.