Checking with other members of the CUPS maintainer team, we noticed hat the only case when lpadmin would ask for a password is when it's run by a non-root user. However, package installation (dpkg execution) always happens under user root. Thus, we fail to see how the issue you describe could ever happen.
Martin-Éric -- To UNSUBSCRIBE, email to [email protected] with a subject of "unsubscribe". Trouble? Contact [email protected]
