It's like that wretched Oxford English Dictionary - did you see those programmes about people trying to add the earliest found instances of particular words and phrases. A case in point being 'nit nurse' - they had elderly people swearing that they knew the name when they were checked out by one at school - but this was NO GOOD as it was merely anecdotal evidence, and It Must Be Written Down. I can see the point of this, but sometimes it was just ridiculous, it was flying in the face of perfectly good evidence.