Shutdown: Allow system to be shut down without having to log on
This security setting determines whether a computer can be shut down without having to log on to Windows.
When this policy is enabled, the Shut Down command is available on the Windows logon screen.
When this policy is disabled, the option to shut down the computer does not appear on the Windows logon screen. In this case, users must be able to log on to the computer successfully and have the Shut down the system user right before they can perform a system shutdown.
Default on workstations: Enabled.
Default on servers: Disabled.
Computer Configuration\Windows Settings\Local Policies\Security Options
At least Windows XP SP2, Windows Server 2003