remove "shutdown" option from gnome system (not gdm!) menu?

[Berna Massingill]

I help administer a lab of FC5 machines intended to be used both by
people sitting at the console and by people logging in remotely,
sometimes to do long-running background stuff.  Because of the
possibility of remote users, we want to not make it too easy for people
sitting in front of the machines to reboot them or power them down.

Unfortunately, in the default setup for FC5, the "logout" menu
option is now part of the "System" menu, right next to "suspend"
and "shutdown".  It seems to be all too easy for people to click on
"suspend" or "shutdown" when they're aiming for "logout", with bad
consequences for anyone unfortunate enough to be using the machines
remotely.

After quite a bit of searching and experimenting, I figured out how
to make the "suspend" option go away (by disabling the "suspend"
option of gnome-power-manager [1]), but try as I may I'm not finding
any way to make the "shutdown" option go away.

Can anyone help?  

Notice that I am *NOT* asking how to remove the shutdown and reboot
entries in GDM's "Actions" menu.  Those don't seem to be a problem
for us and can stay as they are.

It's really tempting to rant about the poor design decisions (with
regard to the organization of the "System" menu) making it so easy
for people to shut the machine down when what they intended to do
was log out.  But maybe there's a good reason ....

Help appreciated.

-- blm


[1] Exact command (and no, I don't remember where I found this):
    gconftool-2 --config-source \
    xml:readwrite:/etc/gconf/gconf.xml.mandatory \
    -s -t bool /apps/gnome-power-manager/can_suspend false