I had a pretty high ranking Shihan do this on me but it didn't work
I felt a forward projection but could easily post. I asked him to do it twice but didn't want to push it further for fear of offending.
Now you would say, well if he had really tried, then he would have broken your arm to which I would say, then my initial suspicion that it's a elbow break technique was correct.
At least the way I learn Aikido, all techniques should create damage when applied with full force and speed against an attacker who is not prepared to the technique. Then once again, I practice Korindo and not Ueshiba Aikido, my way is not your way ...
As for the encounter with the Shihan and your feeling of his in-sufficient technique, the same reasons I wrote below, about you, also aply to him.
Plus if he were teaching, he may have to do the technique on you, exactly the same in repititive manner, even after he recognizes the opportunity is wrong (and variation\ technical shift is required), in order not to break the lesson.
In such circumstances, he may also expect his Uke (You) to assist in generation of the best opprtunity (so the other students will see it and log it in their memories). in some instances, he would rightfully consider you to be a "bad uke" (for demonstrations) afterwards.
Unless you have some kind of a "private session" with a feeling of
pen communications", beware of making any conclusions from such encounters, you do not know his reasons/thoughts/etc.
Now, interestingly, I tried this on some yudansha and asked them to resist and it had VERY different effects. When they tried to resist, it resulted in them almost smacking their face on their knee.
However when trying on my boxing sparring partners, I couldn't get the desired effect even when simulating ideal break of posture. One of the problems is that fighters are taught to resquare their hips to their opponent as fast as possible, making taisabaki, tenkan extremely difficult. Even some newbies who have a good innate fight sense do this.
Your boxing partner, as well as many newbes, may create difficulties to you from one of the following reasons:
1) Your Kuzushi is not good enough,or the technique build-up takes too long. They regain balance ("square their hips"), at this point, no real lock should be attempted. The yudansha give you a chance, and slow their rebalancing (maybe even to stand-still).
2) Your uke knows what is coming, and makes minor shifts that negate the opportunity, and, since you do not control the technique yet, you miss the indications of this.