They don't seem to have mentioned the obvious fact that the middle seat is usually taken by someone who is a companion (and frequently, a housemate) of either t

They don't seem to have mentioned the obvious fact that the middle seat is usually taken by someone who is a companion (and frequently, a housemate) of either the window or aisle person. I think what they really mean is "no two people from different households may sit next to each other". Seems dumb to not sell the middle seat to a family of three for instance.