There is a different in between coaching and giving instructions. In my early life of teaching karatedo, I used to be an instructor but not a proper coach.
After attended Singapore Sport Council's NROC courses and my own self development, I understand that we should be a coach rather an instructor.
Coaching, in effect, not only teaching techiques of the martial art; but it should also include areas such as physiological conditions, biomechanics, psychology and nutritions. Of course, safety precautions must be one of the important factor the coaches should have. As trainees could fall sick or uncomfortable situation at times; proper help should be provided at the shortest tme.
As Sport Science already developed in countries such as Australia and New Zealand, lots of scienctific researches were published. Some of the routine warming up exercises, in fact, are not practical and may cost damages to the body. One of the examples, is the stomach exercise (sit up), if it is done with the wrong posture, then in time to come, would cause low back injuries.
As a coach, he must have all rounded basic knowledge and provide a more safe and pleasant tranining experience to the trainees.
This is my two cent worth of opinion, you are entitled to yours.