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It cannot self-propagate to any Android-based head unit Remember that not that long ago viruses spread through floppy disks. Today, people share USB sticks full of music from one car to another all the time. They also bring their music from their home car to a rental car and back.
I’ve never met anyone irl who used USB sticks full of music. I know the capability is there in most cars, just never seen it. It seems like Bluetooth capability and Spotify/Apple Music landed in mainstream cars too soon after “play MP3s from USB” was added, for that to catch on.
I've been doing it for years, since it's so much more convenient than the alternatives: plug the stick into my car and I have my whole music library there and it Just Works.