See URL for original redhat bugreport / associated patch. sg3_utils fails to power down external hard discs correctly. The patch fixes that. Being able to spin down external drives is required for "save removal". Upstream author has also been notified. See http://freshmeat.net/projects/sg3_utils/tickets/f7a39e1da35
(Ps.: Wrong bug tracker apparently. I wrote the program's author an email.)
Should be fixed in >=sg3_utils-1.29.