True, but the one or two students will also effect the intensity and concentration of some of the other members. They will take valuable instruction time away from the other members that the instructor has to use trying to get them in line again. If the instructor is seemingly picking on one or two students, then there is likely a reason for it. If they constantly disrupt the class or otherwise cause problems, there should come a point where the instructor should ask them to leave the class (if they are not able to change the behaviour), or he should push them to the point where they will either conform or drop out (which it sounds like he may be doing). In the end, if they conform they will turn out to be one of the strongest members and if they drop out then no real loss.