UA's technology and processes are that robust that it can do that reliably? If so, that's news to me. I doubt it works like that so well. Even DL and AA haven't managed it like this.

I would bet if the airline made an announcement, before the flight, that anyone who tries to board out of their zone is booted off the flight, everyone would comply. There are the 95% who play by the rules and the 5% who have to be forced to play by the rules. That being said, the airlines are at fault for not strictly monitoring carry on luggage, both amount of luggage and size. The aircraft are actually manufactured with overhead bins to accommodate every passenger with the appropriate carry on luggage. If the bins are overloaded the airline is to blame.

Yes, but once the airlines allow you to buy your way ahead of those reasonable prioritizations, at the detriment to those efficiencies, the rules of the process ceases to be reasonable.

Note to Flubber2012 - I have never done business linked in any way to the lhgreengrd handle and I never will - and apparently you also missed the post where I stated I had never done this, but I was playing Devil's advocate in questioning the underlying assumption that the boarding process rules were reasonable.

The only reason to jump the boarding order is to hog overhead space. It makes me smile when the gate agents kick back someone who is not boarding according to their zone. The line jumper deserves the brief moment of public humiliation.

I doubt they feel any humiliation. When you have a sense of entitlement, you're likely to feel more anger at someone stopping you than embarrassed for getting caught.

I'd like to buy an argument, please.

One aspect of this debate that seems to have been overlooked is status, earned through long term loyalty to the airline. I fly from Seattle to Denver a lot. I have a choice of four airlines. Alaska Airlines gets the bulk of my business and one of their ways of thanking me for consistently directing my business (money) to them is rewarding me with early boarding once I've earned a certain number of miles flying with them.

Assuming you agree with the awarding of perks (such as early zone boarding) associated with having directed a lot of your business (money) towards a specific airline:

Should that perk be denied or overlooked just because you chose to purchase a less expensive ticket on a given flight?

You're saying boarding priority should be about the price of your ticket for any given flight but you fail to consider that the priority boarding person ahead of you traveling on that $99.00 fare has earned the right to that early boarding by having spent (or directed to be spent) thousands of dollars worth of travel towards that airline.

This seems like a uniquely American problem.

IMO, "sensible" practices are based on F/J/elites, Y+ (if applicable), and Y by row.

One of the reasons for boarding priority I cited was a flyer having status. Yes, that's a reasonable motive for giving someone priority.

^

Those people seem to more likely feel no embarrassment nor have any anger about such situations. I've even seen such people repeat things on the same or connecting flights. The anger is more likely from those who have a sense of entitlement and are formally entitled to board early on during the boarding period -- it's those officially "entitled" who are most likely to moan about this issue and snap at other passengers about trying to board early.

There are two choices - either you award boarding priority on the basis of status and amount paid, or you do it on the basis of efficiency of the entire process. You cannot blend the two in a haphazard manner and still have a "reasonable" set of rules. The rules are either there to maximize efficiency, or they are there to maximize airline revenue and perks to the most loyal customers - which also has a long-term revenue maximizing effect. They can't do both simultaneously. If they attempt to do so, they forfeit the "reasonableness" argument, and hence, it becomes a game with no singular purpose - thus getting around the rules is a winning game play - just as getting caught and sent to the back of the line would be a losing play.

Not if it in any way diminishes the overall efficiency of the boarding process - which was previously cited as the goal

So it's up to you then to determine the "reasonableness" of the rules? What if everyone else took the same approach you do? I suspect more than a few psychologists would not look upon your approach anywhere near as charitably as you do.

I was on a United flight a couple of months ago where the gate agent came on the intercom and said very firmly that anyone who tried to board outside of their assigned zone would have their bags automatically gate-checked.

I was in Zone 1 so I have no idea if folks complied but she scared the crap out of me. I checked my boarding pass ten times!