Thread tags can be abused and mistakes can be made. People often think that they can anonymously post a tag and post abusive words to troll. It also happens a lot that people misspell tags. Its virtually impossible for an admin to find and correct tags on a medium to large board. Simply due to the size. Especially in the case of abuse, flaming, insult its needed to that members can report a bad tag. This way the moderators can take action. Optimally there would be a report center function to remove a tag from the database completely.