see bug #52434 tools which include an option to not use X at all (in an attempt to override the apps attempts to guess if it should use a gui or not, a oft requested feature...) will always get a gui root password dialog box if DIALOG is set. Maybe a config option for stuff like /etc/security/console.apps/up2date-nox that would say "NOX" or something. Not a priority, but it blocks a low priority bug I have, so here we go.
userhelper knows nox in recent releases.