George S. Ledyard wrote:
To us it seemed fairly ridiculous to decide that paired sword was Aikido but paired knife wasn't.
I quite agree.
I've often had a feeling that as nage, techniques esp. use of atemi seem to be designed to be used with a knife in the hand; the atemi that people question, saying, "why would I react so strongly to avoid that?", raises no eyebrows if you imagine the atemi with a small knife in hand, or even just the possibility in uke's mind of a knife.