Lions for Lambs

Has anyone seen the new Robert Redford film, Lions for Lambs? Three separate but related situations are placed in context with each other; a military manoeuvre in Afghanistan, a reporter interviewing a Senator, and a Professor meeting with his student. I'm curious to know what you think, especially about the latter. Politics aside, I was really interested in this (admittedly dramatized) conversation between teacher and student. Without giving anything away, at one point, the Professor (played by Robert Redford) offers the student a "B" in exchange for the student agreeing not to come to class again and to never take another class with him. Was this an acceptable means for trying to challenge and motivate a talented student? I thought that these scenes raised some really interesting questions about the teacher/student relationship. Is the student a customer? If so, what product or service should an instructor be expected to provide in exchange for the student's tuition dollars? Information? A grade? Good advice? Genuine concern? A challenge? What, if anything, does the student owe his Professor?
Link to film clip