....They will snap a photo and send you a fine via mail.
They worked all this out with the red light cameras. Still, sound isn't like light. How are they going to get the right vehicle out of a crowd? I guess some smart guy already has most of this problem worked out.
The way that works in NC is they send the ticket to the registered owner so it doesn't matter who is operating the vehicle. And they will put a hold on renewal of your registration until the ticket is cleared. At least it doesn't count as points against your license.
I got one when they first started. It was $50 and they caught me at a light I had been going through for over 10 years. They changed the timing so only 3 cars could get through before it went back to red. I was number 4. They stopped using the cameras for a while to work out some legalities and came back for good, but with a $100 fine.
....Go to a hot rod shop to buy a can of special spray paint to spray on the plates....
I haven't heard of the paint, but you see a lot of vehicles with those plastic lenses that cover the plates. I'm sure there is some law about placing anything over that plate that will obscure it. It depends on if someone is paying close attention and if you give the officer an attitude when you get pulled over for some reason.