Unbalanced cables that use the arrows have twisted pair cable inside for the "ground" and "hot" leads. Connecting the shield at one end only ensures that crud that is blocked by the shield is not transmitted component-to-component. Balanced (professional) cables generally have the shield connected at both ends since many cables may be connected together in a pro environment and there is no time to waste trying to figure out if this cable or that cable has it's shield connected at only one end. The shield tab isolation is taken care of at the equpment end.