I think this is very much a question with no clear answer. However, I understand that user names can’t be replicated or recycled.
What about how similar user names can be? This could be difficult with the software available, but how similar does a user name have to be before it is disallowed?
We have had recently Cesario - that was a real treat, being confused with him.
Now I see an MTCicero- once again the confusion could occur. (I am not complaining about MTCicero- he/ she obviously has great tastes).
Where is the line drawn?