Yes, I remember now that the first sansa mp3 player we bought had to have that setting changed, but more recently it hasn't been necessary (they seem to last about 3 years). That mystery is easily solved, the default setting is "autodetect" (not present in the early version) so it automatically mounts as MSC. I did try setting the new one to MSC but, of course, it doesn't make any difference.
I think I'll leave it as is and remember Leiche's semi-solution.
Thanks again for your efforts djohnston. At least I've learned a few new commands.