So I'm sitting on an A319 scheduled from SEA-IAD. I'm feeling pretty good as I'm in 6A and the plane doesn't look to be full. Of course, the one middle seat that is assigned on the entire flight is the one next to me (6B).

What is the deal with this? Is that the price of sitting in these seats (exit, bulkhead, front of section?). Are the best seats on the plane, not always the best seats?

I'm a 1P so I figured I was safe. Does anyone know how middle seat blocking works on UA. Is there a method to the madness?

Thanks