mounted multiple times

["Jack Tanner" <ihok hotmail com>]

On an FC4 client, I'm mounting an smbfs filesystem over the network. In 
/etc/fstab, I have

//server/share /mount/point smbfs 
credentials=/home/user/.smbcreds,noauto,user  0 0

The user's .bash_profile contains the actual mount command, which goes off 
without a hitch. Consequently, the user can issue

$ umount /mount/point

when necessary.

It's all well and good, until the user connects to the FC4 client twice, and 
runs two xterms which both source .bash_profile.

Now the mount command has been issued twice, so here's what happens:

$ umount /mount/point
umount: it seems /mount/point is mounted multiple times

Well, yes, it has been mounted multiple times; but how can the user unmount 
it now?