Additional note: "making it work a different way" half-worked. Using gnome-disk-utility to set mount options to generate the /etc/fstab line:
LABEL=Spinner /media/Spinner auto nosuid,nodev,nofail,uhelper=udisks2 0 0
did allow the drive to mount from the disk utility; but after reboot, I still got two icons for each volume mounted this way in the launcher, as per bug #1010858.
I suspect the "correct" way to fix this is to fix x-gvfs-show mount option though, as that seems a more natural and user-discoverable way to get the desired effect (internal volume mounted at boot showing up in launcher etc)
Additional note: "making it work a different way" half-worked. Using gnome-disk-utility to set mount options to generate the /etc/fstab line:
LABEL=Spinner /media/Spinner auto nosuid, nodev,nofail, uhelper= udisks2 0 0
did allow the drive to mount from the disk utility; but after reboot, I still got two icons for each volume mounted this way in the launcher, as per bug #1010858.
I suspect the "correct" way to fix this is to fix x-gvfs-show mount option though, as that seems a more natural and user-discoverable way to get the desired effect (internal volume mounted at boot showing up in launcher etc)