You believe incorrectly..
You'd be hanged either way...
For me, my Mp3 player in the Lightspeed would actually be better, as you can set it to cut out the music when the squelch is broken..
I also think, and I could VERRRY easily be wrong, but with an MP3 player coming into one's own headset, there would be little proof it would be recorded by anything..
I don't see how it would make it into the CVR recording...
I just find it ironic that quite a few of the "no mp3" player guys have no issues with ADF listening..