Quick security question

[Luke -Jr]

Actually, IIRC, the Ctrl-Alt-Delete login process is meant to thward phishing 
attacks. When you press Ctrl-Alt-Delete, Windows ALWAYS intercepts it. 
Therefore, you know Windows itself is presenting your login dialog, not some 
viral program. You can send Ctrl-Alt-Delete remotely since at least Win98 
(though in DOS-based Windows, it will freeze any network processes).

If you want to determine if a user is local, use a USB dongle :)