We have a lab with multiple RedHat EL5 machines running the Gnome desktop environment. When developers are done using the machine sometimes they miss the logout button and click the Shutdown button by mistake (easy to do, I've done it myself). Needless to say, for those remoted into the lab it's sometimes devastating. Is there a way to remove the Shutdown entry for all users from the Gnome menu?

Note: I do not mean Shutdown on the greeter, but the Shutdown button on the menu drop down that is next to logout, sleep, etc.