In my opinion what is needed are some menu options:
MUTE AUDIO AT START (ON/OFF) – Mute the audio system when the vehicle is started.
AUDIO INPUT AT START (Radio, Bluetooth, USB Media, CD, Last Input) — Switch to this input at start or continue with the last input when the vehicle is turned off
I could probably see the first option being “AUDIO VOLUME AT STARTUP”, for those who want audio output but at a fixed volume. Since mute is just volume 0, this might be a better menu option than just mute/no mute.
What’s funny is that suddenly switching to the radio when disconnecting from CarPlay actually violates one of Apple’s design guidelines for CarPlay, which states that disabling CarPlay should not switch to any other audio input unexpectedly.
