Bowwow:
Usually, nobody offers to direct me to a seat.
Also, often the seats that are available have name plates and the seats that are not don’t have name plates.
Also, if I come late, there is more of a reason why I can sit anywhere and assume the guy is not coming.
Also, are you indignant because there is an inyan of “makom kavua” or because it is “your seat”?
Also, I am not brash at all. You don’t own the seat. And if in your shul the people consider it that they do own the seat, you should have a sign on the door that says “KHAL ANSHEI S’DOM” so I’ll know not to come.