Bargain-hunting travelers beware of this potential trend: Germany’s largest airline is suing a passenger who skipped the last leg of a booked flight, a practice called “skip lagging.”

Lufthansa says the unnamed passenger violated its terms and conditions by not completing the entire trip. It’s seeking a bit less than $2,400 in damages.

The precedent has travel industry observers paying close attention.

Skip lagging is a money-saving method where passengers leave their flight at a layover instead of the final destination. For example, a traveler hoping to go to Dallas could book a cheaper flight to Seattle with a layover in the Texas hub.

Airlines aren’t fans of the practice as it can delay flights and ultimately result in higher fares for everyone.

In the Lufthansa case, the unnamed passenger was supposed to fly to Oslo from Seattle via Frankfurt in April 2016. However, they skipped a connecting flight and returned from Frankfurt to Berlin on a separate ticket. His total cost was 657 euros, or $743. The airline says he should have paid 2,769 euros, or $3,133. It’s seeking the difference plus interest.

A victory for Lufthansa could affect skip lagging travelers, who can use the workaround to save hundreds of dollars per flight.

So far, courts haven’t been on the airlines’ side of this battle.

In this case, a lower court in Germany has already ruled in the passenger’s favor, but Lufthansa is appealing. It’s rare for an airline to pursue this action and even rarer for it to pursue it this vigorously.

Lufthansa has a major presence in Europe. In 2017, it took over most of Air Berlin. And its business class cabins are the height of European luxury.