^,^^ I wonder if it is all dependent on whether the phone needs to write anythign to the storage card. I wouldnt' doubt that WMP writes something to the storage card when playing music. Maybe it does some writing to keep track of the last time a file was played, or if you change the rating...

Has anyone tried playing music files on a more basic audio player that may not do any writing while playing the file?

I know this solution would def not be ideal... but it may further the udnerstanding of the problem and may be useful if someone only uses their memory card for music playing abilities...