Well, I suppose I might have been a bit hasty in my reply...but I am starting to see it more of a case of splitting hairs on exactly what it means 'to teach'. Duane, I think, is correct in that one is always a model, even if one is unaware of one's impact on others. I see it more of an unconscious thing...as meant by my insistance that 'a lot more than technique is transmitted'. When training, one is completely present, is 'all there', the whole package focused on the task at hand - in sharing everything with one's partner. The person goes along with the knowledge. (At least, I hope it does.) And, I've learned recently by starting teaching, that that process goes both ways.
Don't want to belabor it, but I'm of the opinion that one should try TO BE a better person, and have only recently discovered that many people do not share that same view. That they are 'fine' and that 'self-improvement' is not necessary nor something to strive for. This is why one chooses carefully one's students. Yes, it sounds very elitist, but I teach and train with people I like. Of similar mindset. As Cord states, folks that resonate.
If the morals passed on by an MA teacher only resonate with the already law abiding, modest and peacefull, then they are not being taught, nor changing anyone for the better.