Memories can fade with time. Another big problem I have is that people, bless their hearts, really want to believe they found my car. There is a yellow '69 GTX about 30 miles from me which does not have a black vinyl top. I have had at least three or four people see that car, and call me sometime later swearing it had a black vinyl top like my car. This is just an annoying part of how human memory works.
Memories can grow with time.
Obviously, not all of these sightings can be my car. I have repeated what people have told me, but much of it must be taken with a grain of salt.