You can find footage on the net..... I found 9 pre ww2 movies (searched "aikido mpg" on google...) Also, theres two on aikidofaq.com.
Anyhow, I've seen what looks like what you describe, and I've seen people who certainly didn't throw themself. I read about (? guy who started yoshinkan?) a judoka who decided the uke WERE throwing themselves who took on O Sensei. I believe he was flying through the air when he realised that they were in fact thrown.
Must be said that anybody taking Ukemi from O Sensei who threw themselves would be in trouble, though. Ukemi isn't about guessing where he's throwing you (which can cause nasty injuries when you're wrong) but letting your body follow softly and be thrown. This would only apply more forcibly in the case of a master endowed with such subtlety in his technique. If you're going to jump first, you might as well struggle maniaclly and take the atemi. It's just as close to good Ukemi.
I believe I have seen the mpgs you described, so I think I know what you are referring to. What I was attempting to describe was a little different from that, but as always it is difficult to convey a technique in words without causing a misunderstanding. Sorry I did not make it clearer. The difference was in a throw that was made by connecting to uke's center and disturbing his/her balance and a throw which occurred as a result of avoiding an oncoming atemi in a situation where there was no connection to uke's center. In my experience, when faced with an oncoming atemi in a situation where nage has not made a connection to uke's center one of three things will result: 1. If uke is able, uke will block the atemi. But this provides nage a potential means of connection to uke's center enabling uke to be unbalanced and thrown. 2. Uke will attempt to avoid the atemi and cause himself/herself to lose his/her balance and possibly fall. 3. Uke will actually be struck by the atemi and fall provided there is sufficient force. If nage delivers an atemi and in the process of avoiding the atemi uke loses his/her balance and falls, I think the end result is just as valid and real as nage connecting to uke's center, unbalancing uke, throwing uke and thus causing uke to fall. Since, I was not able to block the atemi. I avoided it, lost my balance and fell. I did not intentionally lose my balance. That would have been poor ukemi as I am sure you will agree. In retrospect, I don't think I phrased it very well when I said, I threw myself. I probably would have avoided causing any confusion if I had explained it as I did previously in number 2.
As for guessing where nage is going to throw you, I am in complete agreement with you. It is dangerous. Had I been guessing, I would have guessed the technique was going to be performed in the same way as it was on the previous two ukes. In which case, I probably would not have been able to avoid the atemi.
However, if you are advocating taking atemi in the face as opposed to trying to block it or avoid it, (I do not know if you are just being facetious) I disagree. I do not think allowing oneself to be struck in the face is a natural reaction or conducive to safe practice.