Stop the Apple Music app from launching

I too have seen conflicts between CarPlay and the radio. My car's a Hyundai.

I mostly listen to the radio, with an occasional trip where I instead listen to a podcast or music via CarPlay.

What I've found greatly helps is when I finish a trip where I've used CarPlay after I park but before turning the car off I open my phone, open control center, tap the now playing widget, tap the symbol on that for output selection, and make sure it is set to iPhone Speaker. I then hit the Media button in the car and select FM. That starts the radio playing. Then I stop the radio and shut off the car.

Next time I use the car CarPlay connects normally but does NOT take over the media playback. If I hit the play button in the car it starts playing the radio.

This works fine for me because as I said I mostly listen to radio. It is not that big of a deal the once a week or so that I listen via CarPlay to do those extra steps at the end of a trip.

It would probably be a lot more annoying if I was frequently switching between radio and CarPlay.

In either case I would definitely like a setting somewhere that makes it so the play button in the car plays whatever source was playing the last time you turned off playback.

YouTube does respond to it though?

I needed something like this a few months ago. I use my MacBook to run my (musical) keyboard rig for live performances, and use low-latency wireless headphones for monitoring. The headphones have a transmitter dongle that plugs into my laptop, and the dongle sends a "play/pause" command if I press a button on my headphones...causing Music to launch and begin playing audio out of my default output device. It doesn't even care whether my headphone transmitter is selected as the default output device; in a complex multi-device setup, I can press a button on my headphones and it will happily play audio out of some other device.

This is problematic because if I were to accidentally hit the button in the middle of a set, and it decides to default to whatever interface is connected to the P.A. system, then now I've just started blasting some random song at full volume to everyone in the venue.

(It's not an immediate problem for me anymore because I've reworked my hardware setup such that the dongle connects through my audio interface rather than directly to my laptop, meaning my laptop no longer receives "play/pause" commands from it. There were additional reasons for this rework, but preventing this misbehavior was absolutely part of the consideration.)

It's absurd that a premium device marketed to creative professionals has unconfigurable behavior like this which is so unacceptable for a live show.

I had an OO perl replacement for iTunes back in the day (to learn OO perl, mostly). It had a web frontend, and also handled ripping and cd metadata with “insert disk, up arrow enter”. It failed to eject the disk iff there was a problem with the rip / transcode / metadata. I had 3-4 CDROMs in a desktop for parallelism.

Maybe I should have an LLM port to rust. It was under a thousand lines of code.

This question is fascinating. The reason why pressing the Play button when no media session is available should not open the music player is because there is no media session available. Why would launching Apple Music be the desired or even expected behavior?