locking and crash recovery and such - is to use vipw(8).  (Hasn't vipw
   been the recommended way to edit the passwd file since clear back in
   the V7 days?  Why would anyone edit it directly?)

one reason may be that it's only part of the ucb compatibility stuff
in SVR4.  i find that most stuff in /usr/ucb is pretty broken under
SVR4 so most people avoid it.  they have to edit both the passwd and
shadow.  heh.  heh.