Ken McFarland quoted the notice you referenced, but if you click the "more" link, you'll see a photo of Gooch Gap. Not even pedestrians are going to cross that!
Considering how close the Parkway runs to Asheville, Blowing Rock, Pisgah, and others in the news, I would expect a fair number of less dramatic places than Gooch Gap that need to be checked. Too bad: a Parkway without cars would be heavenly!