Empty tags are deleted after 24 hours, if I understand correctly.
Right now, on Mi Yodeya, we have a tag which has been used in the past which we do not want used. It currently has a warning as the tag wiki.
The tag right now has only one question, which was migrated and will be auto-deleted after enough time goes by. At that point, the tag will be deleted, and with it the warning will go.
Aside from randomly assigning a question to host that tag, is there a way to keep the warning? Is there an alternative suggestion of how to prevent users from using an unproductive tag?