mount points not special

[David N. Blank]

Howdy-
  I have had this evil situation happen a couple of times at sites I
administer (by people other than me), and was curious if this is
specific to my opsys (NCR SYSV brand UNIX):
    Under this system a disk is partitioned into some number of
logical partitions.  These partitions are then mounted as separate
file systems at some mount point in the file system tree.  For
instance, attached to /usr can be a file system from another partition
called happy (to become /usr/happy for all of our gleeful users).  So
far so good.
    I have seen situations where someone has done a recursive rm on a
directory higher up in the tree that blows away the mount point
directory (ie. rm -r /usr makes /usr/happy go bye-bye).  Then you get
to argue with the mount command about the status of that partition
'cause someone is getting confused (besides the idiot user who did the
rm in the first place). 
    My question: do other opsys's designate these mount point
directories more invulnerable to rm's, or is mine just dain bramaged?
Is there a bright way to prevent this from happening again (besides
taking the person who keeps on doing this out back to be shot)?
Thanks muchly in advance.
     Peace,
       dNb