In my application, on a Samsung TV, I can leave the app on one full-screen view indefinitely and the screensaver does not activate. Instead after about 30 minutes, hitting the back button from the full-screen view shows a blank screen instead of the previous view. I have gotten a bug from the Yahoo QA team that back should always show a view.
I am not able to debug this as I cannot reproduce the error in the simulator. In the simulator, in a full-screen view, after about 15 minutes the screensaver activates blanking the screen. There is no way to unblank the screen without leaving the application.