We agreed these mass queues are chaos. Experienced them in other locations as well, such as the shows (FoTLK, MILF, Frozen singalong etc) and line for the monorail. Don't understsnd it at all.
It actually makes a lot of sense. The attractions with the "fill in all the available space" instructions are "mass loading" attractions. Hundreds of people, (thousands in the case of FoTLK) are going to see the attraction at the same time. It doesn't matter if you are the 10th person to arrive or the 50th, you are still getting in. So the CMs tell all of the people who have made it past the click-counter (and are definitely going to get in to the next show), to scrunch forward without the need for a line because they have already been counted as being "in". At that point, a long, single-file line is irrelevant.
In the case of Pirates, they don't mass load hundreds of people per boat, but they do load 10-15 on average. The space that is available for the people to scrunch forward is small enough that unless one tries deviously, they can't really move pass more than one or two boatloads of people. And if
everyone follows the instruction to move forward, then it becomes impossible to "pass" a significant number of people. "Passing" only happens when some people follow the instruction and others don't--hence the CMs statement that "if you don't, others behind you will be happy to." If you had an aerial view of how the crowd behavior worked, you would see that very few people actually gain an "advantage" by moving past others, and those that do only do so because the "others" stood still and didn't follow the instruction. So they lose by way of amusement park Darwinism. Once they learn to follow the instructions, they won't be passed any longer. And the people who do move past others don't move past enough people to really matter, unless one is deviously trying to slip past everyone to get to the front. (I suppose that can happen if the crowd isn't tight enough, but is happens so infrequently so as not to matter.) But in general, think about your own experiences. Have you moved past a family that wouldn't move forward? Sure. What did that gain you? You were now ahead of 4 or 5 people who used to be in front of you. In a mass loading situation, that is irrelevant. Odds are, you will all be in the same boat, both literally and figuratively.
So do people enter theaters in the
exact order that they arrived? No. Do people board Pirate boats in the
exact order that they arrived? No. But do people enter/board in a close approximation of the order that they arrived? Yes. And from Disney's crowd control standpoint, this is all that matters. They care about fitting in as many people as possible into the pre-board and pre-show areas more than they care if the 10th person to show up actually enters the theater as the 15th person. Empty spaces cause the crowd to spill out into areas where they don't want a crowd to form. So their crowd control priorities take precedence over "perfect line order".