When I was a TA at Univ. of Michigan I once gave a student an F- because his cheating was so poorly done. I had to check, and it was a legitimate grade. He didn't even put any effort into his plagiarism. It wasn't even interesting to read. (yes, this wasn't out of the blue, he knew it was possible)

wow, F- is extreme.

He showed up to class twice. He skipped the midterm and answered only two questions on the final (both wrong). His paper had large sections copied from the textbook. I was a very forgiving TA, but this kid just didn't care. I could have had him thrown out, but he was doing that on his own, so F-.