I swear by this spray:
I got a ticket once at Airport and Reynolds that I don't think a cop would have pulled me over for. I was approaching the light as it was changing and someone was following directly behind me and I was scared I would get rear ended. No luck in contesting the ticket.
I bought a can of this and sprayed both plates after. It has discolored my plates around the numbers a little (they look a like Larry Sykes plates do in the recent blade photo so he probably is using it as well). I don't run red lights but admit to speeding but still slow down around camera's.
My sister borrowed my car one day and told me she was speeding on douglas by the university and the camera flashed and warned me I was probably getting a ticket and just let her know when I received and she would pay it. Never received a ticket so that stuff must work.