Well for me the conclusion of the logic is that you learn to make fewer mistakes, not more.
I'm sure many people will call rough training "realistic" or any other number of things while actualy being little more than quick ways to wear out a body. I'm usually the first person to avoid injury for the sake of looking tough. Also, I haven't been to many places, but my experience would suggest that while accidents do definately tell you something was wrong, they don't automatically denote laziness. To my mind there are acceptible thresholds of risk established between training partners based on their combination of ability as well as how far they want to push that ability. Operating within those established norms isn't lazy. The accident isn't proof of laziness, it's proof of a mistake in action. Accidents which might be described as the result of deviating from the established thresholds of intensity would denote laziness or worse. I strive for zero mistakes, but I accept they can happen and take precautions. So far I've yet to hit anyone, despite my acceptance for the idea that mistakes/accidents can be viewed as good teaching moments.
Not literally every time, like for techniques which are designed to practice using the tsuba purposefully. If you're not trying your best, then you're being lazy. The tsuba is coincidental to that fact of training.
Sure, it's what you ask of your students and doesn't necessarily need to be adopted by anyone else, and I'm not making a case to suggest it's ok to damage anyone. Our ukemi for the kirikaeshi involves dropping the front hand in case tsuba doesn't do the trick. I've never been hit on the knuckles because I also use tsuba. As my practice got better, the need for tsuba diminished. Most of the techniques I've practiced, the tsuba is just along for the ride. Removing the tsuba is adding risk by removing lines of defense. All other thing being equal, it's adding pressure to the training by removing some of the things used for adding to the protection, which can be viewed as demanding higher standards by creating a degree of risk. I'm sure it's compensated for through a measured degree of intensity based on that.
In this case I consider the use of tsuba as locking your door even though you live in a safer neighborhood. I'd put my sword away, but all I have at the moment is this pen. Strange that it looks like a keyboard!
Matthew. You state a case without addressing my questions. Do you rely, depend, on that safe environment?
Do you see that bottom line dependency on own ability and self far, far, exceeds any 'thing' you think protects you.?
Some people would rather not see this because it would show they have been lazy in their thinking.
I would say all top professionals in all walks of life use this attitude. It's what separates the top sportsmen from the rest. They blame no one, they focus purely on their own ability and improving it, and every time they make a mistake they blame themselves and reprimand their self for being lazy. Such is the upper echelons of discipline.
I doubt O'Sensei or his deshi at the time used tsuba on their bokkens. I wonder why?
Anyone can use special circumstances to make a point. A good excuse not to look at the concept.
It's a good topic all of it's own this topic of dependency and laziness and fits especially well in martial arts for that is one of the core things it's meant to teach, self reliance, self discipline. All about self and the lesson that laziness is the result of dependency.