I am EBG and just flew CPH-AAL a few weeks ago, where I have chosen in advance a window seat for me and the middle seat for my partner. But after we got on the plane there were a passenger on the aisle seat, while all the other rows around me had middle seats empty.
I am curious if I chose the middle seat and my partner chose the window seat, will they then block the aisle seat instead?
When booked in economy we always book window and aisle and leave center seat free, often seat block works fine...and if not, we have never, so far, experienced a fellow passenger who is not happy to trade her or his center for the aisle :-)