For some reason, I am not allowed to remove tags without adding in a relative tag. I (like probably most people whose contribution is mainly answering questions) really only want to help people with things I am interested in and have some relevant expertise in. Sometimes questions (usually of very low quality but perhaps close to the median of this site) are mistagged as having to do with something close to my area of expertise. After reading a question like this, I have no desire to look through a list of tags for the asker after they have already wasted my time, but I'd like to be able to do something about them.
In many fields, there is often no (or at least not very many) moderators with enough expertise to determine if a question belongs to a tag. I am requesting some sort of "untagged" tag, which people with reasonable amounts of rep can change a question to if it is tagged incorrectly, so that experts can determine when a question is mistagged without having to go through the hassle of fixing some 4th graders homework for them.