Disbelief
>"In my experience, when an unqualified observer sees an unusual object or event, even if he is scrupulously honest about what he relates, he has a tendency to embellish the observation each time he recounts it."
They may be just passing on the excitement, trying to give you a good visual.
For instance, people who have close encounters are either telling the truth, or they are lying.
I doubt you can "embellish" a close encounter.
You'd have to experience it first to know there's no way to downplay it.