Re: Live tanto in grading
We use a live blade for tantodori in our yudansha exams.
I would add that for us it is not that we're trying to recreate a realistice knife attack environment, as has been said before it wouldn't work very well and people would get cut if the attacker was coming in with any knowledge of how to use a knife.
For us it's more like the difference you get in iaido when you start using a shinken. It shifts your focus.