Ahh... the required "guest" account with no password on it.
In SGI tech support (East team '96, Unix team '97 - my Indigo was dewi.csd.sgi.com), it was the way we copied files around (the Troops had just come out) and also had a internal tool that would pop up a window on someone else's machine to get their attention (if they weren't directly paying attention to the multicast chat program...)
I remember SGIs having incredibly poor security, at least with IRIX 5.x. Authentication for X11 was totally non-existent in the default configuration. If someone was logged in from the console, you could pop windows up on their screen (and sniff the keyboard) from remote.
> Ahh... the required "guest" account with no password on it.
That plus the lack of a default /etc/shadow, because reasons, made for fun times. ;-)