Well TarHeels... on two of those, you just know, someone in the group in front of you snuck the ball into the hole, since you couldn't see the green. Just kidding. (I think)
My only hole-in-one, in Hawaii, was similar. The par 3 was the last hole and it was almost totally dark. I knew I'd hit a good shot, with full view of the green, but I didn't see it go in. But nearby, on the practice putting green, the head pro and assistant pro began dancing around and whooping it up. I was playing by myself so I couldn't have had two better witnesses.
I was playing a Titleist and received a very nice trophy with a place to put the ball. But several years later I was low on balls so played with it. Yep, lost it!