I can see why people might be upset by things like this, especially the 'unnecessary' use for merely undesireable behaviours instead of just for dangerous behaviours, but where all other techniques have failed it means the pupils can still be taught. The alternative is no education, no chance for them to interact, less controllable by their parents or guardians, and generally a more miserable life.

Given that alternative, as long as usage is strictly monitored and controlled, I would advocate this system.