Here's a better system "Will all you folks who need to board right away, then block the aisle while you figure out how to jam your huge oversize rollerbag into the overhead, please board now.
Everyone else (that is, those of you who have a clue, and those who have actually been on an airplane before) please wait 15 minutes or so until the aisle is clear. Then we'll be able to finish boarding in 5 minutes, and you can be on your way to _____".
;-)