From what I see in your original post, this is a message to a channel, so hardly one-on-one... every client in the channel will receive that message, and if there s a services client in it, anope will too.
And from a quick look at the unreal code sendto_one() wants a nick, not a nick + host..
Anyways, why on earth would you think that the nick!username@host would be send with every message???
That would be a major overhead... hell, when using tokens unreal even replaces "PRIVMSG" to save on bandwidth.. if a client wants to know the host of a user, that client has to send such a request to the server.