Such concept as "appropriate attack" simply doesn't exist.This is a cheap excuse that usually is used by not well trained instructor, that is not able to execute a technique correctly. There is simply 'an attack' and the instructor have to deal with it.

If you read my post carefully, you will see I was talking about teaching principles, and not merly teaching techniques. As every basic principle is contained in any technique, it doesn't matter what technique instructor is doing, as long as he respect the pronciple that he wants to teach.

You still not reading my post carefully. I was writing about teaching principles, not about beating up a poor uke.
I'll give you an example: lets take unbalancing.
You can demonstrate unbalancing from static attack or dynamic - doesn't matter it will be gyaku hanmi katatedori or yokomen uchi or choke from behind.Uke can counter instructor technique by double leg take down or by simple escaping back- still instructor can demonstrate unbalancing. It can be demonstrated in standing techniques as well in suwari waza and in hanmi handachi waza.In this context, there are no limits here. That is why I see a 'code' for uke as useless and damageable for students.