Originally Posted by MitsMarty
then I didn't understand the suggestion of leaving the Receiver on if you still gotta get the remote.
You only asked for something that could turn on automatically, and you don't need the remote to turn it on if you just leave it on.
1)Apple TV in on state: TOSlink light is on even when no audio is being pushed to it, though a receiver could easily know if there is active audio.
It would have to switch to that input first and try decoding it in order to see what if anything is being transmitted.
I think a good designed autosense ON/OFF for AV receivers would be a very marketable option, surprised it doesn't exist.
Look at all the complaints people have here about auto-sensing subwoofers that don't turn on when they expect them to. It would be much worse to have your receiver turning off and on and switching inputs when you didn't expect it. There's no market for this, and if you think it through you'd probably realize you don't even want it.
Based on your stated requirements so far, what should work for you is an AV receiver with AirPlay support. Leave it always on or in network standby mode and it should automatically switch to the internal AirPlay input whenever you start playing something using AirPlay.