Good question. A lot of things are assimilated subliminally.
I think that the answer is probably yes. A smooth out of focus image will help to emphasize whatever is in focus and won't distract in the way that images with bad bokeh can. Just don't expect them to articulate precisely why they feel that way.
Interestingly enough, it's something I noticed as a child, long before I ever touched a camera. I also remember noticing the punch holes (aka cigarette burns) in projected films (I remember thinking it was weird that I'd never see them when the same movie was on TV).
The changeover cues would be there but with wide screen movies that got cropped at the sides on old 4:3 CRT television sets you wouldn't see them. With B&W films they were usually black dots. With color they were usually yellow, almost a metallic gold. And with anamorphic films they were oval, not circular. When I worked for a university film program that ran mostly older films, we often had to make our own since there wasn't enough of the end of the reel to give us time to do a proper changeover from one projector to the next. 35 mm movies used to come on 20 minute reels and there were two projectors so you could change from one reel to the next without the audience being aware of it when the projectionist was in good form and the print wasn't too beat up.
Yes. It is mentioned from time to time in American Cinematographer articles. Cinematographers know that a small detail like light falling on the subject, with no plausible light source evident in the shot, will disturb and distract the viewer, who will not be aware of the reason for feeling disturbed. The light for the shot may come from a professional source, such as an LED fixture; but since the viewer doesn't know it's there, the scene must include a secondary light source called a "practical" that the audience can see; even though it isn't really contributing that much light, it has to be there to convince the viewer that what he or she is seeing is genuine.
