It's entirely my own thought. I am new to the whole IP thing and am trying to make sense of it in terms that I am already familiar with. It is most interesting to me that some aspects of it exist to a degree in some styles of Aikido. I definitely felt this for the brief time I practiced with a Renshinkai group.
Unbendable body also make sense but it requires constant intention to be so. And the intention is the key I guess. But it's big no-no to be so in dojo since it can easily irritate nage(or his ego).