Lufthansa just billed a customer $2,300 to cover what it claimed the customer owed for a trip he had already taken and paid $780 for in full. Why? The customer who lived in Frankfurt had bought a round-trip ticket from Oslo to Seattle, with Frankfurt connections. He paid the published Oslo-Seattle fare of $780. To take the trip, he bought a cheap ticket from Frankfurt to Oslo, and then took both outbound connecting flights. On his return, however, he did not take the Frankfurt-Oslo connection and instead remained in Frankfurt. And Lufthansa said that because he didn't return to Oslo, he owed Lufthansa the published fare of $3,080 for a round trip from Frankfurt to Seattle.
This is an example of a longstanding ticketing hack variously described as skiplag, point-beyond, hidden-city, or throw-away ticketing. The basic idea is simple: Sometimes the nonstop airfare to a traveler's intended destination is higher than the one-stop fare to a second city, beyond the first, on flights that connect at the intended city. In that case, a traveler heading to the intended city buys the connecting fare to the second city and just doesn't take the connecting flight.
Another form of throw-away ticketing has become scarcer. Formerly, on many routes, one-way tickets cost more than round-trip tickets. So a traveler could cut costs by buying a round-trip and not taking the return. When the cheapest round-trips required a Saturday night stay, travelers could buy two round-trip tickets for a short trip, one starting at each end of the trip, and throw away both returns. These opportunities have been cut dramatically as low-fare airlines introduced one-way ticket pricing throughout much of the nation.
Lufthansa's move is just the latest in a series of occasional airline attempts to stop travelers from using the throw-away ticketing gimmick to cut trip costs dramatically. In 2018, United threatened a passenger with going to a collection agency and/or canceling his frequent flyer credit and status unless he paid a $3,000 fare difference. Over the other years, other airlines have done the same. Threats include confiscation of frequent flyer miles.
The "legality" of throw-away ticketing is murky. All legacy-line contracts of carriage specifically prohibit throw-away ticketing, and airlines claim that travelers who use those tickets violate their contracts with the airlines. But, at least as far as I can tell, the hacks are not illegal, in a criminal sense. Airlines have threatened travelers with collections and other forms of coercion, and they have successfully claimed payments from travel agents that issued throw-away tickets. But I know of no criminal prosecutions that have been initiated against individual travelers.
Another hack that hasn't seen as much publicity is the throw-away land package. In some cases, airlines sell air-hotel packages for less than the lowest airfare, using "tour basing" fares that are lower than any simple airfare. So you can buy an air-hotel package, select the cheapest hotel available, and throw away the hotel voucher. Or you can even find a good hotel option and use it, paying less than the lowest airfare and room rate separately. This has been going on since before deregulation, with full airline connivance: I remember TWA packages to London years ago that included one night in a Scottish guesthouse for considerably less than London tickets alone.
If you're considering a point-beyond ticket, you need to know the risks:
-- You can't use point-beyond for most round-trip travel: As soon as you miss a connecting flight on the outbound leg of your trip, the airline cancels the rest of your ticket, including all return flights. The only round-trip on which it works is one where you miss the last connection on your return trip.
-- You can't check baggage on a point-beyond ticket. In most cases, airlines will not check bags just to a connecting airport.
-- You run a minor risk of re-routing through a different connecting city.
-- With any throw-away ticket, the airline may pressure you to pay the difference.
If, despite the risk, you're looking for point-beyond opportunities, skiplagged.com searches for options on any route you enter.