I don't know if it's the same over there, but here in New Zealand, when you take scrap to the metal dealers you have to show them photo ID - usually your driver's license, plus give them your address, phone number and vehicle registration number ('tags').
There have been ongoing copper thefts everywhere - guttering off churches and old houses is a popular target.
There have even been reports of bronze plaques being stolen. Brass/bronze fetches not a lot less than copper.
A few months back a couple of guys were caught stealing man-hole covers (either forged aluminium or steel) and there was a case not too far back of someone trying to steal copper bars from a substation that was very much alive with 400,000 volts.
From our local news:
"They are cutting into live conductors and risking blowing themselves up. The last one we had we found burnt rubber gloves at the site. We had one about six months ago where they stole copper from a substation and as they cut it out of the ground it caused an arc and it blew the pliers out of their hands and we found the burnt pliers.
We had an incident in a small town where a truck hit a power pole and the lines fell down around him. A very helpful passer-by went and cut the lines from around the truck, which was an incredibly dangerous thing to do because they could start up live at 11,000 volts. By the time we got to the site they'd cut them, rolled them up, put them in the back of a utility ('pick-up') and driven away".