I almost...ALMOST thought this was a Porsche. Then I realized my mistake. Porsche snobs are way too Euro trash for Harley Davidson stickers. Now if that were a Triumph sticker then he might'a fooled me.
Actually, it could be that he likes to picnic in the great outdoors, and the car compliments that interest by featuring a built in picnic table.
I did not take this picture in South East Georgia, so I cannot comment on whether or not the owner can read.