Absurdly Driven looks at the world of business with a skeptical eye and a firmly rooted tongue in cheek. 

No one enjoys getting a nasty letter from a lawyer.

Except, on occasion, an even nastier lawyer.

One United Airlines customer, however, wasn't entirely enthralled after getting an unpleasant missive from the airline.

As Jon Nickel-D'Andrea at No Mas Coach describes it, United sent a threatening letter to the husband of a friend of his for the perfectly legal -- but, some might say -- morally dubious way he used his airline ticket.

Essentially, airlines sometimes offer tickets to a destination via another destination. They can be cheaper than booking a direct flight to that connecting airport.

Some passengers who merely want to go to the connecting destination book those tickets, with no intention of reaching the claimed ultimate destination. And they make sure they've got hand luggage only.

The practice is often called skiplagging, after a website called  Skiplagged, which tries to find as many of these deals as it can. (Without making a profit.)

In 2015, United tried to sue 22-year-old Aktarer Zaman, who created Skiplagging with his clever technological skills. It lost. The airline claims it was on procedural grounds.

Some might think, though, that United's lawyers ought to be as well versed in procedures as its Gate Agents and Flight Attendants are.

Now, though, the airline is making fascinating legal threats to those who observe this practice and use Skiplagging.

The letter Nickel-D'Andrea presents is a moving one.

United accuses its customer of skiplagging 38 times. Then the threats commence: 

Such conduct constitutes fraud and a violation of Rule 6 of United's Contract of Carriage. Accordingly, United demands that you cease and desist these unauthorized practices immediately and that you reimburse United in the amount of $3,236.76 which represents the difference between the cost of the tickets that you purchased and the cost of the travel taken, within 10 business day of receipt of this letter.  

I'd always thought that fraud was illegal, yet there's no evidence skiplagging is. It's not as if the customer promised to pay the $3,236.76, did he? 

Still, United threatens to make use of its remarkably strong corporate arms, and not for hugging: 

If you do not make the requested payment, United Airlines reserves its right to take further action, including submitting United's claim to an outside collection agency, terminating your MileagePlus membership and/or refusing to transport you on future flights in accordance with Rule 21 of the Contract of Carriage.

I'm not sure you could call it customer service when you're serving notice on a customer that you'll try to, say, ruin their credit score.

Naturally, I contacted United to ask what some might see as a slightly pernicious attitude. I'll update, should I receive a response.

I can imagine that some might wonder about the morality of such customer behavior. Yet, in 2014, the New York Times' ethicist Chuck Klosterman pronounced it perfectly fine with these words:

Purchasing something doesn't mean you're obligated to consume it in totality. You can use whatever portion of the purchase you choose. If you buy a loaf of bread, you don't have to eat every slice. 

Sadly, it seems that United is merely miffed about not making the maximum amount of money.

Which is peculiar, given that only the other day the airline's CEO Oscar Munoz insisted that raising baggage fees wasn't because United really wanted to make more money.

Even more peculiar is the fact that, with its threatening letter, United is menacing a regular, paying customer. Just like it did with Dr. David Dao, after he refused to be bumped from a flight and ended up with bumps all over his face.

All that skiplagging customers do is take advantage of a loophole in the airline's own systems.

I can understand that United might want to warn such customers -- in a friendly manner -- that they're taking advantage a little too often, just as stores do with customers who return purchases a little too often.

Sometimes, you have to accept that some customers are clever, or even a touch slippery, and deal with it in an intelligent way.

Threatening to wreck a regular customer's credit score doesn't quite classify as intelligent.