[TriLUG] Alternate root user

[Kevin Hunter]

This web site

http://industrial-linux.org/ilg/security.html 

mentions creating an alternate root user and booby-trapping "root".
Seems like a great idea, but everytime I try to create a user, either
w/ uid 0, or later changing it to uid 0, it fails, saying not a
unique uid.  I know how to do this in FreeBSD ( chfn, pwd_mkdb ), but
I cannot find any details on how to do this in linux.  Do I have to
change root's uid to something non-0 first??

KH