This is what is posted about it on the ATC website:
" Date Posted: 02/05/2003
Subject: VANDALISM - US19E/Bear Branch Road
Trail Information: U.S. 19E/Bear Branch Road: Hikers are strongly encouraged not to leave their vehicles overnight where the A.T. crosses U.S. 19E (at the intersection of U.S.19E and Bear Branch Road) in Carter County, Tennessee. Vandalism has been a significant problem at that location for many years. Vehicles have been stolen, burned, or vandalized as recently as March 2001. Hikers are encouraged to choose alternative trailheads or seek out local businesses who may allow you to park your vehicle for a fee."
In other words a bad apple or two work that location. If you are just hiking thru, you should be okay. Problems like this exist other places, not only just on the AT. It is a sad commentery on the world in which we live, but that is the way it is. View the ATC website for additional info and also you can contact the local ATC Club, which maintains that section of trail for additional info.