The intimidation approach is arguably inappropriate when dealing with graduate level students, yet, something needs to be done to protect the valuable time of other (prepared) students the classroom. Negative discretion might be useful — but for students that are chronically underprepared, a lower grade is of little import. As for the on-deck circle, I think it is a a good compromise, and reinforces principles of resposibility and mutual respect. Some form of peer-pressure would likely be most effective. The notion that to be unprepared is simply unacceptable must be a sine quo non of the law school classroom. One professor of mine granted positive and negative discretion, but permitted any student to notify him before class (without any negative consequences) if he/she was unprepared. This protected the vitality of discussions, expressed a respect for professor and student, and helped to create a rigorous learning environment where students expected much from each other and our professor.