Meanwhile, the primary reason is the windows are effectively unused. Actually go out and sit in your drivers' seat. Look in the rearview mirror and you will not be able to see those windows. You obviously aren't using them on the drivers' side when changing lanes (you can't even use the one in the passenger door), and to use the one on the passenger side when changing lanes has you turned around more than you're ever going to turn around while actually driving. If your side view mirrors are even CLOSE to adjusted properly, you shouldn't have a blind spot even close to what you'd be able to see out there anyway. Passengers in the back seat aren't going to spend a lot of time turned around facing backwards either. If you have a dog in the back (as I often do), you MIGHT be concerned with the dog's ability to see out, but crack the back window and he/she will forget all about it. If you're camping, you sleep with your head at the back of the vehicle, AND you want to see out (versus keeping the sun down until you're ready for it) then I can see it being a negative.