Nikoloai.....
You may complain that checking at the door is stupid but I've seen PAX board the wrong planes all too often. I've seen BMI Baby pax boarding Ryanair, I've seen FlyBE pax boarding a Dash-8 with its engine stripped and Ryanair pax boarding BMI a/c, maybe there wouldn't be so much of a queue either if more people used the backstairs aswell!