Where I am more concerned is when the structure is the highest point in the area, however the lighting always seem to strike further downhill because the lower elevation trees are more conductive than the higher elevation rocks. A fellow I worked with has this exact situation. He asked my opinion as to whether he needed a lightning rod system. I suggested that he talk to a lightning protection professional, however my personal opinion is that he should not put in a system because the lighting is already not striking his place. I believe that if he adds lightning rods, he will just attract the lightning to his house.
In this situation, adding an extremely good ground rod (well casing) will make his electrical system much more attractive to lightning strikes.
Larry C