Scrapping can be big money, and there is crime involved in some of it. Around here if a house is empty for any period of time somebody comes and rips the plumbing out of it making it worthless and then the city has to tear it down (happens to empty commercial buildings as well). The guys doing it cost the local area a bunch of money and something had to be done.

There will probably be some major consolidation going on over the next decade where small time buyers will get baught out and you will have only large state liscensed corperations buying scrap with locations in all the big states. It is getting hard for anyone making real money scrapping to get out of paying taxes on it.