Word of advice. Don't fight it. You're better off just paying the fine and moving on. You'll end up wasting your time trying to argue. They've heard everything. Most Judges and Officers know exactly how to fight every excuse under the sun, and they've done it hundreds if not thousands of times.

Also, about signing the citation, over here in CA it is a requirement for the Officer to get a signature, as it is an acknowledgement of your intent to appear in court (or pay the fine). Don't know how it works in over there, though. I have a feeling it really isn't going to matter, since it will still get filed by the Officer, and it still goes on record.