Obviously a lot of posts to a simple question.
I consider the extra questioning of my documents as an added piece of security by the airlines. There are methods on which some could enter the plane after the gate and bewteen the aircraft. Its also appears to be used to better direct the flow and lessen the boarding time.
One thing you do not want when first boarding, especially on a long haul is to get CC placing a Red Flag on your seat number.
Also something I note once in a while is passenger attitudes when there is a delay. Had one recently going through Paris. Two hours late arriving from JFK (big surprise there). People were at the desk demanding this and that and yelling at the staff as though they had created a problem.
I have found that over the years its great to be in line behind one of these people and when your turn comes, just be nice, what can you do for me, please and thank you. The staff relaxes it allows them to focus and I have actually gotten a bump up with a kind attitude.
Try it sometime.