Treatment of "difficult" students
I'm curious how other instructors deal with students in their classes that for whatever reason, purposely act difficult with their training partners? By this I mean students who consistently strongly resist, shutdown, or counter their junior training partners on the mat. I'd like to be clear I'm not referring to students who are too rough or hurt their partners.
For instance, their is a senior kyu student in our dojo who is always trying to resist, shutdown and counter students junior to him. I and others in the know usually avoid bowing in with him, but occasionally it can't be helped. In the past couple of classes where I have been paired up with him, he was up to his usual old "tricks." The instructor for both of these classes happened to be by sempai. Well, on both of these occasions, the instructor saw what was going on and basically made this student take some, fast, constant and rigorous ukemi for about five minutes straight. The end result? Took the fire right out of the guy, and he was for the most part a good practice partner for the remainder of the class.
So, how have other instructors handled these types of students?