Yes we used to run a SCO Unix server. We had an administrator who was responsible for the backups insisted in logging in as root.
One day on the production server he entered
rm -r *
and pressed enter (he was in the / folder).
About 10 minutes later he came out of the computer room and said that he was having a problem with the server.
When I went in and looked at the screen I started laughing and he couldn't work out why... I called a mate in and he laughed as well (we were not in any way responsible for this system). They learned how good their backups were and the administrator was quickly moved on.