[@Ellri] An alternative to having a blacklist on members who can use the tag would be the inverse: Having a whitelist for members who have proven themselves dedicated to mentoring and helping others (or at least have not been aggressive or harmful in the past). Perhaps one could apply to be allowed to use the tag, a mod could check them over, and then give them permissions to use the tag. There could even be an added Title or other flair that states when an individual has the mentoring authority, either just on their profile or also under their avatar on posts.