Well, well, perhaps I found some info:
http://forums.sandisk.com/sansa/board/message?board.id=shaker&thread.id=121
Thank you for contacting SanDisk Technical Support.
Please be informed that the player does not support purchased songs. You can only transfer regular mp3 files to the player. These Mp3 files are not licensed.
Should you have any other concern with our products, feel free to contact us again.
Best Regards,
Now, the above *was* with regard to iTunes. I thought Amazon downloads were indistinguisaable from tracks I had ripped myself, but perhaps not…? (Never thought I’d have to worry about the technical details of such… 
)
