Larry Clinton At Frankfort, (Central) Indiana
Had to smile, I have noticed homes with "security" storm doors with fairly heavy bars and less than 10' away (and in a more concealed location) is a 3' wide window! To me a reasonable lock that requires something visible to be damaged is as effective as any unless you have steel shutters locked and covering every window.
Much like locking your car, it deters the common thief, obviously any determined thief can break the windows of the car, but many just try the car doors to see whats inside. If locked they pass your vehicle, as a broken window may draw attention and have the police investigate.