Since you are in the UK, you are used to having your life videotaped and different laws. Here is how that DIDN'T work in los angeles when the photo radar things first came out.

1, you speed and get caught on film
2, you get a ticket in the mail
3, you throw that crap out
4, you get another notice once you miss the court, which you also throw out.
5, eventually you get pulled over or notified by the DMV that you have some massive unpaid fine
6, you never signed the ticket, which is your agreement to show in court, and the fines and associated stuff get thrown out because thats how it worked. Even better if they arrest you, since the fight goes to false arrest and grounds for a lawsuit.

This is mostly changed now, especially since the systems take multiple pics of your car and face. If your front plate or face are unrecognizable, they can't get you. Plate is easy, take it off. I'd rather pay a $10 fix it ticket for no front plate than a $250 red light violation at 4 am...