That assumes running emacs locally, what is being discussed is if you
are running Emacs remotley, i.e. over a remote X11 connection (e.g,
ssh -X).

Oh, sorry, my bad. I'm surprised to discover that it's apparently the remote
application's job to ensure that it has a proper title when run remotely... 

For ssh connections at least, I guess that emacs could check if a ssh variable
such as SSH_CONNECTION is set in the environment. But I'm not sure how
robust it would be.