In fairness, the "Switch User" button is a terrible interface on many levels. Apart from the complete lack of feedback on the actual situation (an active deskto

In fairness, the "Switch User" button is a terrible interface on many levels. Apart from the complete lack of feedback on the actual situation (an active desktop session), it conveys a muddled mental model in which someone who has logged out and walked away from the computer is still considered to be "The User". A better interface would simply have the normal login prompt, along with some information about any active desktop sessions. The computer is no more "locked" than it is on first boot.