Netflix is tracking the physical activity of some users’ who own Androids, according to The Next Web. Recently, a security researcher found that the Netflix app on his Android requested permission to access the device’s physical activity sensors. The reporter who broke the story also checked and realized the Netflix app on his Pixel 3 XL was already tracking his movements, without his knowledge.

“We are continually testing ways to give our members a better experience,” Netflix told The Next Web. “This was part of a test to see how we can improve video playback quality when a member is on the go. Only some accounts are in the test, and we dont currently have plans to roll it out.”

While it’s unclear why Netflix would want to track physical exercise or movement, it is common for people to use the Netflix app when they are running on the treadmill or commuting on a bus. Some reports suggest Netflix wants to utilize the new activity recognition permission on Android Q to help optimize video streaming while in motion.