Surely if someone is doing a waza incorrectly the person will be embodying the wrong method of doing the waza? This in time would become habit forming and in my mind in a negative way.The guy having conditioned himself to doing incorrect waza then has to re programme himself over again.
Not only that surely you as the visiting instructor at a seminar have a duty to see /check that the students are doing what you show them rather than what they believe your demonstrating?What would be the point of inviting you to teach them if they carry on doing what they normally do?Seems a waste of valuable time money and human resources ie you.Hope you are well> Cheers, Joe.
I practised once with two Japanese shihans (both 8th dan) on two different occasions for about one hour each time and there was hardly any verbal exchange at all. On many occasions the waza did not work, but I had to figure out for myself what was wrong. Both work-outs took place some years ago and I still remember them in some detail -- and incorporate some finer details in my own training.
Hope you are well.