Well, I'm sure it's possible to completely fool even you with just mIRC. Yes, there are many identifying differences between clients that opers use to identify client vs bot vs drone, etc .. but nothing is impossible to emulate or "cloak".
What I don't get though, is why is it so important for the clients to be using Java? Is the Java client disabled in such a way that prevents the user from seeing information they should not see? If this is the case, and since the IRCd and Client were both designed by the same people... why dont they just disable/hide whatever it is they want to disable/hide on the server end of it?
I can't imagine how possessing an mIRC client could be any more disruptive or give the user any unfair power, unless the client sends colors or uses a script to flood the channel... both with other servers can block with existing channel modes. (strip colors, flood limit)
- Raccoon