This might be the dress code in question:
Pass riders’ overall appearance should be well-groomed, neat, clean and in good taste.
Attire should be respectful of fellow revenue passengers, employees and pass riders.
Pass riders may wear denim attire (such as jeans), shorts that are no more than three inches above the knee and athletic shoes when traveling in Coach or Business cabin.
The following attire is unacceptable in any cabin but is not limited to:
Any attire that reveals a midriff.
Attire that reveals any type of undergarments.
Attire that is designated as sleepwear, underwear, or swim attire.
Shorts that do not meet 3 inches above the knee when in a standing position.
Form-fitting lycra/spandex tops, pants and dresses.
Attire that has offensive and/or derogatory terminology or graphics.
Attire that is excessively dirty or has holes/tears.
Any attire that is provocative, inappropriately revealing, or see-through clothing.
Beach-type, rubber flip-flops
CUSTOMER SERVICE'S JUDGEMENT WILL PREVAIL IN ALL MATTERS PERTAINING TO THE DRESS CODE."
I pulled that from here: http://www.flyzed.info/UA
A variety of the participants online (twitter and elsewhere) guessed that the people turned away were non-revs before UA confirmed, and there was a bit of commentary on whether the dress code was enforced uniformly (specifically: did the man in the group's shorts violate the length rule, or is this just another one of those Policing Women's Bodies things, like what happened to Nicola Thorp when Portico told her she had to wear high heels, which had all kinds of fantastic repercussions for dress code legality in the UK).
People who were already familiar with pass riders/non-revs generally were accepting of the idea that it is okay for airlines to enforce some rules on non-revs, as this is a privilege or benefit and it comes with some strings and one has to play along. Some took this a bit farther, moving well down the path of "Kids/Unwashed Masses/Millenials These Days".
I would like to make some observations about dress codes.
If a dress code exists so someone who is offering something of value can make a monkey do a trick in order to gain the something of value, then the argument that, "hey, these are non-revs, these are the rules" would make sense. I am _reasonably certain_ this is not the actual reason for the dress code. Altho, I could be wrong.
If a dress code exists so as to avoid giving offense to the paying customers, then this particular dress code probably needs to be adjusted, since it seems to be freaking out and/or pissing off paying customers, and the only defenders (other than UA, the source of the policy) seem to be taking the, hey, I'll be your trained monkey if you give me free flights approach. Which, as I noted, is not much of a defense. I will give my readers a little hint about how business works. You generally want the _paying customers_ to be pleased with what you are doing, and you don't really care too much about the people who are attempting to use your service for free. I know, airlines are a little screwy on this -- even JetBlue has taken to running advertisements along the lines of, '"I'd prefer to pay for my flight," said no one ever.' Really, JetBlue? I mean, I love JetBlue, but thanks for calling me No One. I have said exactly that. I fucking loathe frequent flyer programs, the customer behavior they encourage, the accounting practices which have mutated as a result, and the corporate insanity that has grown up as a result of those frequent flyer programs. Airlines are often _very not clear_ on how important it is to treat the paying customer with some respect (FlyerTalk DYKWIA forums are full of tales of the unwashed masses in First who paid for their tickets being treated badly by members of various elite programs who think they should get their seat as an upgrade instead. The unwashed masses love posting about this when it happens, because It Is Hilarious, but if we didn't have frequent flyer programs, this would stop happening. Probably.).
Returning to the dress code issue: In my entirely anecdotally based and unscientific opinion, boomers tend to like to show a lot of leg, gen x'ers tended to show more skin in slices (ew, that sounds kinda gross -- slits, v's, midriff, etc.), and Millenials tend to cover up a lot but wear very body conforming clothing. There are a lot of boomers, but they are flying less. There are even more Millenials, and they are flying more. (Wondering why I'm not mentioning gen xers her? Hey, just following the trend, which is to pretend we don't exist.) The dress code UA offers up (if I actually have the right one) shows some clear evolution: they've already given up saying no to jeans, sneakers and shorts, which I'm prepared to guess happened when the boomers were a lot younger than they are today. I'm betting there will be some changes to reflect Millenial attire.
And now, as long as I'm here, and assuming no one else read this far, I, for one would much rather see a Grooming Code that specified things like, Please Brush Your Teeth and Do Not Wear Scented Products. Bad breath in a seat mate is icky, and I'm allergic to nearly every fragrance ever invented.
In airline related commentary -- but having nothing to do with UA or leggings -- I watched the recent NCIS:LA episode, 767. I wish it hadn't been called a 767. I mean, if they'd picked a different jet, then at least some of the things they did on that plane (the crew rest quarters, maybe) would have made sense. If they hadn't _specified_ a jet, equally fine. But no.
Based on this, I think they must have actually been on a 777.
Maybe the 767 in the title referred to something other than the aircraft?