My god. Here we go again. Perhaps you can get the radio to turn off permanently by pressing the volume button for 3-4 seconds but it has never worked for me. I NEVER listen to the radio. I listen to apps, I listen to music through my phone and I listen to audio books. If you do any of these activities and turn the car off, the next time you turn the car on it defaults to the radio at the volume level you were listening to the previous activity. It does not remember you turning the radio off the last time you selected the radio. It remembers the last time you used the head unit and then turns the radio on, at that volume level, the next time you use the car.
SO if you listen to an audio book or you talk via the head unit and turn the car off (without lowering the volume before you do) , the next time you start the car the radio will come on at the volume you did the last activity.
I am simply saying (and many have complained about this issue) that if you set the radio to Serious XM’s station 0 then it will default to a silent radio station so you don’t have to remember to always turn your volume down to 0 before exiting the vehicle.
If this doesn’t bother you or you have not experienced the same issue please ignore this post. This is not a competition on who is the most learned Subaru owner. I know what is happening in my own car and I am simply sharing my experience.