Is this a discussion about music or in-car entertainment systems? Hell, we were once told to turn down our car stereo when we were paying Jez Lowe's Jack Common's Anthem (thanks Helen!xx). I don't suppose it really matters what sort of music you're playing in your car, or at home, or wherever, just as long as it isn't playing too loud... I have a similar objection to folkies with PA systems, but that's another story, albeit similar!