At least the victim was able to fight back and stop the robbery, despite getting shot in both legs.  Open carry would have been a greater deterrent, obviously:

Rally's shooting: Robbery victim speaks out | ksdk.com | St. Louis, MO.

Two would-be robbers picked the wrong victim yesterday, quickly finding out that he was armed too. The shootout that followed happened in the parking lot of a St. Louis Rally's Restaurant.