Re: Ukemi vs. Protecting your attacker
Uke's shouldn't "jump" into a high fall. The high fall is a natural consequence of them being connected to their own wrist, and the movement of nage. It should be something that is done in a controlled and relatively safe way - nothing jumpy about it. However, I don't expect an untrained attacker to do it - I expect their wrist to break.
Aikido techniques provide a wide spectrum of responses, not just "bringing uke to the ground in a controlled manner". Sometimes we want to do that, sometimes we want to break their arm, or drop them on their head.
As an aside, I was surprised to see the result of someone not following a strong kotegeishi in our dojo recently - broken ulna and radius, but no damage to the wrist joint itself. I'd always assumed there'd be some tissue damage long before the bones went. Ah well (no, it wasn't me).