Another day, another bad headline for United Airlines.

Maybe this is just how it's going to be now. It's hard to imagine hiring more midlevel PR people will to make much of a difference, but it's also possible United might not really care, for a very good practical reason.

We'll get to that in a second. First, the latest oh-my-God moment:

You may have read that a bride and groom from Utah say they were escorted off a half-empty United Airlines plane Saturday--on the way to their wedding in Costa Rica, mind you--for allegedly sitting in an empty Economy Plus row when they'd paid for only Economy class seats.

The couple says they moved to the better seats because there was someone sleeping and spread across their assigned seats, when they boarded in Houston--and that a U.S. marshal was called to remove them. The airline says that's not true; that the passengers "repeatedly attempted to sit in upgraded seating which they did not purchase and they would not follow crew instructions."

A United spokesperson also told my colleague Chris Matyszczyk, "no air marshal or authorities were involved. The passengers followed our crews' instruction to leave the plane."

An unwinnable argument.

What's the truth? Who knows? I haven't seen video, like the passengers' accounts that went viral after the airline had security officers come aboard to remove Dr. David Dao. (He wound up bloody, beaten, and planning a lawsuit.)

Regardless, you might wonder why United wouldn't just want to get out in front of these kinds of PR nightmares, given all that's happened in the last week or so? For example, if people try to sit in empty Economy Plus seats, maybe just look the other way for a bit.

Maybe don't threaten a paying first-class passenger with handcuffs for not wanting to move to economy (to make room for another passenger you managed to sell the same seat to for more money).

Heck, suppose someone gets attacked by a scorpion on one of your flights. Maybe go way out of your way to compensate them, and let the world know what an amazing offer you made to make them whole.

Because with each viral story of bad customer service, we get deeper into a spiral of even worse brand reputation. And you can imagine some passengers might now think they can push United more then they might otherwise; trying to to get extra perks in the hope that United is fearful enough of more bad press to acquiesce.

Yeah, you might think that. But you might be entirely wrong--and for a really good practical reason.

Why United doesn't have to care.

I don't know if it bothers the employees of United Airlines that their employer's brand reputation has taken such a beating, but there's a practical reason why the airline's leaders might not care very much.

It's that United is one of the four airlines that control 85 percent of all flights in the United States. According to Bloomberg, that's up from controlling 55 percent of all flights a decade ago.

Related, while United's stock price has fallen roughly 2.8 percent since news of the passenger-dragging video broke last week, it's still way up since last summer (about 68 percent from its bottom last June), and way, way, way up from when United merged with Continental in 2010.

All of which means two important things. First, passengers for many of United's routes don't have any other options. Second, their strategy--as much as many customers and would-be customers say they hate the way they are treated--works from a business standpoint.

In other words, you might say you're shocked and appalled at the way passengers were treated on United. A lot of people might agree with you, and be moved to tears by some of these nightmare customer service stories.

Nevertheless, United and its shareholders might reasonably reply with indifference. So what? They're laughing all the way to the bank.