I believe this is actually an absolute block (removed from inventory) for all flights occurring on the 752/3's through the winter season regardless of route. This is more than just a blocked seat on the map but the seat maps updated as if the seat didn't exist at all so it can't be released/not even a gate agent can assign it. My understanding is there is also some physical modifications being made to make it clear the seats aren't available to be occupied (though if anyone happens on a 752/3 and wants to wander back to one of the seats to let everyone know, that would be great).