[CentOS] C5 & C6 : useradd

useradd --help

-d, --home-dir HOME_DIR home directory for the new user account -M, do not create user's home directory yet useradd -M -s /sbin/nologin FRED

produces in /etc/passwd

fred:x:504:504::/home/fred:/sbin/nologin

Trying again with

useradd -d /dev/null -s /sbin/nologin doris

gives a CLI message

useradd: warning: the home directory already exists. Not copying any file from skel directory into it.

and in /etc/password

doris:x:505:505::/dev/null:/sbin/nologin

QUESTION

What is the 'official' method of creating a user with no home directory and no log-on ability ?

Thank you.