MIAMI — A recent pricing error on United Airlines’ fares allowed thousands of people to book trans-Atlantic flights from the United Kingdom for as little as $50, along with business and first class for under $100 by selecting the Danish Kroner as their form of currency.

But what was missing from media reports on the fare glitch is that in order to attain these prices, customers had to intentionally misrepresent their location by filling in their country as Denmark to take advantage of the currency exchange error. The U.S. Department of Transportation (DOT) said it is “unfair and deceptive” for a seller to increase airfare after a sale, but in this instance, the customers also knew they were taking advantage of an obvious error. This fact will likely keep United out of trouble with the DOT in this particular case.

Another important factor is that United filed its fares correctly with their distribution services, and it was one of its third-party vendors that made the exchange rate error. If it had been an error directly attributable to United, the airline would likely be held accountable and forced to honor the ultra-low fares.

United began sending fare cancellation emails the same evening they were discovered, stating that an error in the exchange rate was what caused the pricing glitch. With thousands of people reserving flights at thousands of dollars below the correct price, honoring the ultra-low fares could have cost United several million dollars.

(Credits: Jeremy Dwyer-Lindgren)

In a statement, United Airlines said “several thousand” people had attempted to take advantage of the error caused by an incorrect exchange rate programmed by a third-party software provider.

Looking at travel dates for early March, on an average day, United charges $8,600 for a roundtrip first class seat from London Heathrow to Chicago O’Hare, so a $85 fare is less than one percent of the normal ticket cost. This not the first notable pricing error for United, or any airline.

In 2013, United honored mistake fares that included $10 from New York to Hawaii, and $250 from New York to Milan, but voided fares for a $49 New York to Dublin error involving Mileage Plus points. DOT said it is  “looking into” the matter and reviewing customer complaints in regard to United’s voided fares.

In recent years, the Internet and social media have become the primary source for those seeing rock-bottom air fares. A multitude of sites constantly monitor pricing services for fare anomalies then share this information with their readers and also on Twitter and Facebook.

Once the word gets out about an error, it spreads like wildfire and has the potential to do more harm than good for those who were hoping to secure those fares for themselves. The more attention an error is given, the more likely it is that an airline will be quick to shut it down and try to void the deals, which is exactly what happened with United.