When passwords are being entered, they're always displayed on screen in plain text, rather than asterisked out. Why? So you can see how clever either the characters or the writers are being; often it being some kind of reference or pun. Part of the office-variety Viewer-Friendly Interface. In a futuristic setting, the password may even be spoken to the computer. In the future, nobody minds if the Bridge Bunnies know The Captain's security codes, especially since computers at that point will be smart enough to also make sure the code is spoken by the correct voice.