Sending the play command itself would be less of a problem if iOS wasn’t so completely opaque as to what “currently playing” or “default music app” means, but that distinction itself would require more clarity as to whether apps can be run in the background or not.

Agree that a "play" command is being sent from vehicle. This autostarts Apple Music if nothing else is using the speaker.

This drives me crazy as I don't use Apple Music and I don't want to keep playing handful of songs I bought 15 years ago on iTunes. I've yet to find out how to disable this.

Delete the Apple Music app from your phone.

I don't have an iPhone. But at least on OSX I didn't find a clean way to remove Apple Music.

Every time I accidentally tap play on my bluetooth headset it opens Apple Music and asks me accept the ToS, which I happily reject. It's a daily thing for me because it's almost impossible to put my headphones on without triggering a play due to bad button placement.

You can try remapping the button. Not sure if it would work, but try: https://superuser.com/questions/554489/how-can-i-remap-a-pla...

Yep, I have it disabled. My main music apps are “Picky” and Bandcamp, and it works pretty well.

When they do start autoplaying in the car (Picky does it), it’s at least whatever I album I was last playing on the app.

Couldn't the phone provide an option to disable this on a per-device basis?