Yeah, the reasons I have seen stated have to do with it opening out into the traffic if you are on the side of the road. If I had one built I would get it constructed as you pointed out. I look out the rear view mirror a whole lot more frequently than I have flats on the side of the road. I would prefer to have the spare tire blind spot on the left side of the vehicle. I may not be the brightest around but I think I could keep the carrier from swinging out into the road in the event of a flat.

1997 4Runner Limited 4x4, 'lectric locka