回複：這正是費解的地方

Notice and opportunity to be heard are the anchors for due process. For a criminal law matter, the court must make sure you have notice and are offered an opportunity to be heard. These are constitutional issues that the violations of them would override everything else. By asking you to sign the ticket, the cop will have a proof that you got notice and offered an opportunity to be heard. Without signature, I am sure notice issue will be brought right up in a trial.

Redlight camera tickets for example. These tickets are mailed by companies like redflax to violators. Many people just ignore them and claim they never receive the ticket--never got notice. A defendant can subpoena the proof of service. Without it, the prosecution does not get a second chance. The case will be dismissed.