Because if you don't log in and try to sign your 
normal name, your post will be rejected with the 
error message "Somebody already has reserved that 
name" or something to that effect.  If you have to 
change some characters in your title, it's easier 
to just put "not logged in" or "nli" if you don't 
want to go through the login process.

And if that was a rhetorical question, then I'll 
apologize for the long, drawn out reply.  I really 
need to find something to do, don't I?  (Could 
always go study those kinetics problems...) >_<