When I was teaching a few years back, I had a student turn in a paper that was obviously not his work. He listed a couple of websites as sources, but when I checked them I got 404 errors. Getting creative, I started peicing together URLS using the beginning of 1 URL and the end of another. Viola! There's the real source. When he got his paper back with a big '0' on it, he was irate. I explained that I had found his real source and he still didn't get it. The conversation went like this...
Student: "But I worked hard on that"
Me: "You did? How? It was someone else's work."
Student: "But I typed it"
Me: "Well, that was dumb. Why didn't you just copy & paste?"

Student was speechless.