Yes, if the signal is coming from HDMI. The receiver (VSX1326) responds to my 3-year old Sony TV via HDMI actually. Turns on and off when I power the tv. I assume any newer electronics that support HDMI signal will do the same.
You can switch back and forth with the pioneer app that controls the receiver. Once you take the receiver out of airplay then your apple device will also automatically stop playing.
Airplay has been flawless for me over the year. Your wifi has to be strong and fast of course. Wifi N a no brainer and dual band. That way when you do airplay the startup to send the signal over is a second I stream and then it will go on uninterrupted.
Take note though the was over my AirPort Extreme. Last Friday I switched to a third party wifi router due to a new cable box subscription and it doesn't play nice with airplay. Doesn't also play nice with my apple airport connected. Still looking for a solution. If you use apple airport exclusively as your wifi router, it will work flawlessly.