With Blender 2.75, you can use face selection in order to paint certain areas only. Do this by enabling face selection which Kent uses to reveal a wire frame, however with blender 2.75 you have to select the faces which you wish to paint on which is why you have to have all faces selected to paint(Thus removing the desired wire frame effect that Kent demonstrates). By only selecting a certain area you can limit where you paint. Hope this helps.
