I got an 89.4% in a CS class and asked the professor, whose office hours I frequented, if he could bump me up to an A since I was so close.
His response was: "If you truly understood the material and deserved an A, you would have earned an A by a large margin rather than missing it by a small one."
I agree with the sentiment, which is why I liked some of my professors who graded in statistical clusters (of course, economic professors). They graded on a curve, so everyone's grade was bumped up by the process, never down - and the clusters of A's, B's and C's were usually obvious. If you were in between a cluster (an outlier case) most gave you the benefit of the doubt and bumped you up.
Of course, I may have liked it less if I wasn't always in (or above) the top cluster =P
I knew that the cutoff for an A was 90%, and I also knew that the grade would be calculated based on my projects and exams. I knew the exact weight of each project and exam too, all within the first few days of class.
I knew what was expected of me in this situation and didn't deliver, so it was my fault for not getting the A - not the grading system's fault. But my 89.4% was so close to an A that I somehow felt entitled to getting one, but as his quote points out, I didn't really deserve it.
I think the point isn't whether or not it's ethical (full disclosure in college would make it so), but whether it's a smart way to do things. I claim it isn't.