I've been to a server where they made players who have not logged in to be inflicted with the blindness effect so they know for sure that they have not logged in. I think this would be nice as i believe many players would had tried to move around or whatever, but annoyed by kept on being teleported back to the same spot just to realize that they have not logged in.
Just suggesting... this could make players know for sure that they are not logged in... (: