disable shutdown/reboot in GNOME logout menu

[Ben Steeves]

Hi Folks,

I've googled around for this a fair bit but haven't found anything
that seems to work:

I have a lab full of machines running Fedora on which I need to
disable the logout and reboot options from the GNOME logout menu.  
These lab machines are used to run long-running
mathematical/scientific apps, and when they get shut down by a
well-meaning person at the console, it can affect the work of other
students.

I trolled through gconf-editor, but couldn't find anything that popped
out at me.

I know the argument that it doesn't matter if shutdown/reboot appear
on the menu since the user can just hit the power button, but there's
an important psychological difference.  A user is more likely to chose
"shutdown" from a menu than hit the button on an up-and-running server
that doesn't provide the option to shutdown.

A post I found on-line suggested that chmod'ing /sbin/shutdown and
/sbin/reboot to 0700 would fix the problem, but that didn't do it. 
Another suggested deleting the shutdown and reboot users, but I don't
see that they're related to the GNOME logout menu.

Any suggestions?
-- 
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