I agree it is SO obvious, but have you ever tried to question one of them? When I am the first to board and sit down next to one that has pre-boarded 10 minutes earlier (flashing that ID and chatting with the GA), I love to ask them who they know or if they work for NWA or if they are a pilot or other VIP. They get all clammed up and try to avoid answering. As if it were a secret!