Just to clarify, I have a projector. I left the video paused and walked away, got caught up in something and came back hours later and it was still running. I’d love to avoid this happening again to me or others who use it. Thx!
Pretty sure it is activated on mine. Its backdrop and turn on a few minutes after the video is paused. With new images every minute i think. Later my TV go to dark mode. And later TV goes off (with CEC switching Shield off)
I don't know if it's a limitation with the official YouTube app, but SmartTubeNext usually goes into screensaver mode after a while when I pause a video to do something on my Shield.
EDIT: Actually, check the Settings -> Device Preferences option on the shield, if I remember there should be a screensaver option somewhere there.