It actually opens up the armrest for the neighbor because it keeps you from needing it for your arm. In which picture do you see more available armrest space (left or right)?

Look at it this way:

Window seat: use the window side armrest

Aisle seat: use the aisle side armrest

Middle seat: proper flight etiquette dictates the middle seat has priority over both armrests. Even so, we designed the clamp to be very non-intrusive to your neighbors. We have flight tested it almost 1 million miles and never had a complaint from a neighbor (we even ask them if it bothers them).