A friend of mine and I almost committed Student Darwinism in college. We were saved by a glib explanation and an almost too-nice professor!
We took a sociology class together, and much of the classroom discussion for a few weeks revolved around experiments in pushing boundaries, like the Milgram experiment. We had a paper due around that time, and my friend and I were working on writing it. We ended up writing the entire paper together. When we were done, my friend said, "So, were you planning on changing any of this before you handed it in?" and I replied that I was probably going to change the conclusion and maybe a few sentences here and there - enough to make it different. She suggested we print out two copies and put both our names on both papers.
We turned it in to the professor with the explanation that we'd written the paper together, didn't want him to think we were plagiarizing, so were telling him outright. We also mentioned we felt it was an experiment of sorts - to see how he reacted.
I thought for sure we'd have to re-write it, or get a lower grade, or something! When we got our papers back though, our papers were clipped together with a note that said, "Had I known in advance you were doing this, I would have held the paper to higher standards. As it is, I graded you the same way as everyone else. In the future, note that professors generally do not like to be used in experiments without first giving consent." The grade was an A, of all things!
We did take his note to heart, and stopped writing papers together. Which we thought was a shame, since I generally had the grammar, spelling, and editing part of it down pat, while she had the creativity and ideas!