I have a fair number of sites and every page on every one of them is original content. Over the years many of my pages on many of my sites have been copied, scraped, ect. Every now and then I check out of simple curiousity. I have never sent one e-mail to any of these people and I have never spent any time trying to combat the problem. My income has been steady as a rock (knock on wood) for years and my positions for any of my sites do not appear to have suffered because of scraping.
This chasing of the scrapers and copiers seems like a lot of unnecessary stress and wasted time to me. I can understand if you have images you don't want people hotlinking to.
I'm not saying people are wrong to chase down copiers and scrapers, only that my personal experience has convinced me it is not necessary and therefore a waste of my time.