I often see the word "unregistered" as a part of a nickname:
What does that mean, is it just a somebody who are not registered on the site?
Why they are allowed to post questions then? If a person doesn't bother registering, they probably won't put more efforts to the question itself. Usually they post a couple of vague phrases, or an unintelligible wall of text, and then disappear. Community can salvage their question thereafter, but is it worth it?
Here are examples of questions from "unregistered":
Hand Crossbows and Ranger Woodchippers in 5e? (see the edit history)
In the latter example the question was closed, then edited and reopened by the community, not the original poster.