/etc/passwd, /etc/shadow, and /etc/group. (By hand, NOT
with passmgmt.) Slaps on setuid bit; tells a nearby secretary to
handle new accounts. Usually, said secretary is still dithering over
the difference between 'enter' and 'return'; and so, no new accounts
are ever created.
motd.
Since people without accounts cannot read the motd, nobody ever
fulfills the bureaucratic requirements; and so, no new accounts are
ever created.
# cd /home; mkdir "index.html#ob's home directory"index.html## echo "index.html#ob Simon:gandalf:0:0::/dev/tty:compress -f"index.html#> /etc/passwd