Players that cause safety problems are always my first focus on both team and lesson environments and that refers back to the idea of requiring compliance or leave. An example might include someone tossing a racket or hitting wild balls intentionally. Those situations aren't acceptable.
Punishment vs Discipline
Injuries are a real risk. Some sort of reprimand or penalty makes sense to me for a team situation. If a team member is a slacker, I might tailor something to test their discipline such as boring and repetitive drills. I always stayed with tennis focused training and never want to be the cause of an injury.
Harming team members or students under your control is not acceptable. We know much more now than decades back. Heat exhaustion and cardiac risk is a major concern. Other injuries can be debilitating and ruin a sports career. All of these are counterproductive. Coaches should be aware of the risk and act accordingly.
