My two cents...
1. As a student, how would you feel if that happened to you and what would you want done about it?- As a student, I might be a little frightened, and very confused at the time. Afterwards, I'd likely still be confused, and maybe even a little perturbed - seeking revenge? Probably not. But I would be wary of diving anywhere near this instructor again. It would not put me off the sport, but others may be differently affected.
2. As an Instructor, would you ever do such a thing and if so, what justification do you think you have to do so in a public quarry.- Well, I woudn't in any way "shove" someone, but might sign to them or their instructor to turn around, or to hover off the edge if a student was having a particularly difficult time with an exercise which they were more comfortable with not having an audience on.
3. Had you been our Instructor in this incident, what would you have done underwater at the time of the incident or later after the incident if given the opportunity?- I'd have gone for "safety first" for my student. In this case, I'd have probably made sure my student was stabilized, then given him the "crazy" sign, and laughed it off underwater, and encouraged him or her to practice neutral buoyancy for the remainder of the stop (or helped them physically maintain if they had problems). On the surface, I'd have made it clear to them that that behavior was very abnormal, and not to expect divers to behave that way, further emphasizing the "community" that are divers...we know the general uptake is one of comaradarie, and team spirit. I would also let them know that that behavior is unacceptable for an instructor and that it would be "addressed", so they don't have to worry about it from them again. As for resolution, at the very *least* this instructor needs a direct consultation, review of the incident face-to-face by a respected peer or supervisor, and more (or a complete repeat) of training with a review before being allowed to instruct again. At most (which is probably overkill) jail time and permanent removal of dive status. The solution is somewhere in between.
4. Would any of you go back to that quarry if you knew the assaulting Instructor was an Instructor working at that quarry's dive shop?- It depends. I would want to know that said instructor was re-trained and evaluated, and approved by a respected professional, and have had a chance to personally consult with them...if necessary with a mediator before considering it. If I was not satisfied with any of these, then the answer is no, and in that case I guess it would make sense to post the times this instructor would be diving.
Is this really "one strike, you're out?" I don't know. Some of this behavior may be coming from higher up - how this individual was trained may be the problem rather than the individual themself...if that's the case it *has* to be addressed at the root of the problem, which may or may not be the instructor themself.
My two cents (perhaps dollars)....No matter what though, it sounds as if you are a high-ethics, high-quality instructor, and can reach a solution.
Feel free to PM me if you'd like to chat more, or get on the horn with the most ethical dive instructor I know who may have some more clear-cut advice than this.
Regards,
-S