I do agree that eye witness testimony can be very unreliable. It is a logical thought pattern to realize that events can happen quickly and somebody may not be aware of what is happening before their eyes. What somebody thinks they saw is not entirely factual. But that logic does not apply very well to CB accounts. To flip this around to your experience, if you were allowed to observe this thief walking around after they stole the purse, would you then be able to describe him better? If you saw/heard this thief interacting with another person, would you then be able to describe them and this other person better?
If CB assumed it was HB boyfriend outside, then why the need to look out windows in front and back of the house, to observe what he thought were the silhouettes of them kneeling in the garage, why the need to call his mother about HB car still being there and people out by the garage, etc... I think it is safe to assume that at best, CB did not know what he was watching, but he was watching, as oppose to saying he just assumed it was the boyfriend, because apparently he did not. Unless, it was common for CB to watch HB and boyfriend go on about their business and call his mother at work to ask questions about them when they are at the house with him.
I think after all this time, CB accounts don't add up to anything, as far as the public is concerned, but we can't just brush it of by saying all eye witness testimony is unreliable.
We have all went around this merry-go-round about CB accounts before and I think it is safe to assume that his stories have some truth to it, but the story is very murky and muddled and no attempts have been made to directly clarify any details.