The Importance of a Direct Line Between the Towers

A friend of mine went up the tower, but was allowed to put on some abseiling kit and climb out of the very top. He says he remembers seeing lots of desert, but can't recall seeing anything in the distance. So if you use exactly 6,371 kilometers of the earth, then you've got a good 260 meter clearance off the ground. It's not going to be that. But I feel like that's enough of a safety that there should be a direct line between the top of these two towers.