Admitting responsibility with an explanation will not be very helpful, as it will not lessen the fines or potential points. Requesting an informal hearing is a better course of action. You will meet first with the police officer and perhaps a resolution can be reached. Failing that, a magistrate will hear the case and render a decision. If you disagree with the outcome, you may then request a formal hearing before the judge. This, in effect, restarts the process and you might still attain a favorable result. You raise a couple of interesting issues that might be worth discussing with an attorney. Good luck!