It is and it isn't. I'm not going to endorse any boarding system, but I will say that the official boarding policy and what is actually being implemented are completely different. What I have personally seen is that the GAs call GS/1K/PP/F/P/C and then less than 10 seconds later announce, "We'd also like to call any 1P/2P/G/S/*G" which results in a mad scramble. Call the first group and then wait a minute or two. While waiting, board the 'super-elites' and then when the line looks smaller announce for the second group (or a further subdivision thereof). IME the mayhem does not result from not leaving the carpet open, the mayhem results from calling EVERYBODY at once.

And I know that the 1Ks will disagree with me here, but it is nice to see the change on UA to allow me as a 1P to get to boarding late (like from a tight connection) and still have preferred boarding.