Retricting shutdown is a bad example. There are environments where a local user has no access to the power switch and reset button. For example, a public "kiosk". Vandal-proof keyboard and trackball and display, metal enclosure locked shut and permanently wired into the electricity supply (ie no plug). Inside sits a plain ordinary PC.
Or the systems I was using this afternoon in a library. Just a hinged cover glued over those buttons, cable-tied shut. A Mollyguard. (Molly, age 5, thinks to herself "what does that button do if I press it"? )