'Requires' directive in spec file ignored?

I've never seen this one before:

I'm developing an RPM, with a %post scriptlet that invokes some
classic UNIX commands (grep, sed, etc.).

I can build my RPM, but I found that the commands in my %post
scriptlet weren't showing up as automatically-found dependancies
for my RPM.  (rpm -q --requires -p foo-1-1.i386.rpm)

So, I went ahead and expressly added them as requirements:

  Requires: /sbin/chkconfig
  Requires: /bin/cp
  Requires: /bin/grep
  Requires: /sbin/service
  Requires: /sbin/ldconfig

My RPM builds just fine, but these expressly-stated requirements
_still_ aren't being reported by the RPM.

So, I chased which RPMs provide those resources:

  Requires: chkconfig coreutils grep initscripts glibc

And _still_ the requirements aren't being reported by the RPM.

This is under CentOS 5.1.  I reviewed my build of the RPM under
RHEL4 update 5, and it had the same symptoms.  The other umpteen
dozens of RPMs built over the years seem to honor the 'Requires'
directives.

Has anyone seen this symptom before?  I have no idea how to diagnose
this, other than instrumenting python code...

FWIW, I haven't redefined any macros, or anything...

-- 
Brian Reichert				<[email protected]>
55 Crystal Ave. #286			Daytime number: (603) 434-6842
Derry NH 03038-1725 USA			BSD admin/developer at large