We had a rash of that thievery here a few years back. Then the state started enforcing the ID law and it stopped......
The sad thing is copper wiring is being pulled out of beautiful, old, vintage street lights - which the city then replaces with industrial street lights.
No one checks the scrap metal dealers in the dicier parts of LA - I used to work near one, the kids told me constantly they never ask for ID for metal - used to see a long line of shopping carts loaded with all kinds of metal - probably stolen - when I passed by in my car.