I can't believe it. I just finished grading an end of the semester extra credit assignment and found three people plagiarising. That's three out of about thirty. 10%! on an extra credit assignment!
Why would you risk an F for the course for a few extra credit points?
Do they think I don't really read their papers? Do they think I'm too stupid to figure it out? Won't care enough to turn them in?
I know that lots of kids do lots of dumb things, I've done plenty of dumb things myself, but the payoff on this is so low and the risk is so high.