Microsoft previously announced that a Kinect is a required component of the Xbox One. Although its functionality does not have to be used in all games, it does need to be connected in order for the system to function at all. This has led some to worry about possible video and audio data the Kinect could take while being connected.
Although nothing Microsoft says will ever deter the most exciteable of privacy advocates, they have posted a FAQ by the title of "Privacy by Design: How Xbox One and the New Kinect Sensor Put You in Control." Upon setting up the system users can choose whether they want an automatic sign in via Kinect or to do so manually. When playing games, you can also pause Kinect. However, it doesn't seem there is an option to have it paused by default upon playing games or media.
The standby mode of the system which waits for a user to say "Xbox On" can also be changed to have Kinect off when the system is off. Microsoft also assures users that none of the data the Kinect tracks will leave the console. If prospective Xbox One users still fear the Kinect then at least they have the option to unplug the system when not playing if they're still determined to buy one.