It's actually a problem with people breaking into unused houses and ripping out the wiring. Or stealing other metal.

Scrap yards in my state (and I'm sure many others) are required to take identification from anyone that sells them metal.

Copper recycling can be quite profitable. Enough so that people rob houses under construction just to recycle it for cash.

There is a very lucrative black market in "recycled" copper. It's been known to be stolen off trucks by the tonne.