If the user(s) haven't got the mod activated then they're not ghosting or breaking any rules, even if they are driving in the dark for those with it activated. Without forcing the mod to be activated for all users (ruining the experience for those that don't want it), I can't see a rule being added/changed.
The administration team used to post announcements in-game regarding having your lights on due to the wintermod, whether or not this still happens I don't know as I don't play much. <-- Admins, feel free to chime in here regarding this