I don't know if this is exactly the same problem, but when running gparted on the feisty herd 3, it mounted the disks as it's working on them too. Also, unmounting through the gparted interface simply leads to gnome remounting them.
-- gnome-volume-manager mounting Partition, while working with GParted https://launchpad.net/bugs/37768 -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
