Previously on my Apple TV I could log out of my account and delete my ID by deleting previously used email addresses, but now constantly I get a screen popping up asking me to log into my account and detailing my email address. This is on a demo machine, and i dont want to be logged in and dont want third parties seeing my personal email address. How do I stop this screen appearing? I have deleted all users. This device is mostly used for Airplaying.