LH...buried in the middle of your post above is: "... as I think is very probable,..."

and what a discussion we could have over just that qualifying phrase.

I can't even imagine how to assign degrees of probability to such an idea. "very"? "kinda"? "extremely"?

There are other possible ways to explain why sane, honest, responsible people 'see' UFOs, AFOs and such...and why some report being abducted by them...etc. Since we are still trying to cope with many thousands of sightings and NO clear pictures or hard evidence, I'd think it would behoove us to investigate a bit harder what we can study...ourselves. I don't mean we should quit looking for hard evidence of AFOs, just that we need to be more open to the 'possibility' that our very complex minds can create false or altered memories in some cases.
We KNOW this does happen...ask any one who has interviewed 6 witnesses to the same traffic accident....or who has had an intense dream that felt 'real'..(I have had two)
I don't mean to denigrate the seemingly clear, intense memories of honest people who are trying to cope with real experiences....but there ARE several possible explanations for most of them, including "it was real, but made here on Earth".
It is quite a jump to say, "I saw it, it didn't fit patterns I am familiar with, therefore I will posit creatures who can violate the laws of physics as we know them, and who 'found' us in a universe of trillions of galaxies, and are able to keep us from really identifying them."
   Yeah..I have to admit...that IS one possibility. *shrug* I just think Occam's Razor leads me...so far...in other directions.

YMMV