This seems completely intentional so I'm not sure whether it will be considered a bug or not; however, /etc/rc.d/init.d/nfs contains the line [ -s /etc/exports ] || exit 0 which is, for lack of a nicer term, obtuse. Why does the system assume that if there are no filesystems being NFS-exported, no filesystems will be NFS-mounted?
*** This bug has been marked as a duplicate of 10646 ***