A flight from DC to Milwaukee via Chicago might be cheaper than flying non-stop to Chicago. So you add the connection from Chicago to Milwaukee, even though you don’t plan to take it. That’s throwaway ticketing.

You save money, but you’re breaking airline rules. You think you’re buying a seat on both the DC to Chicago and Chicago to Milwaukee flights, and you should be able to do whatever you wish with your seat (take the flight or not take the flight). The airline thinks they’re selling you a ticket from DC to Milwaukee and argues that’s a different product than a flight from DC to Chicago. Airlines have tried to crack down on the practice for years.

A reader was recently approached by American Airlines customer service staff at the airport and warned against throwaway ticketing. Here’s their story,

I booked a hidden city ticket …[Charleston to Philadelphia to Washington National airport, and s]aved a few bucks, maybe $25 or so [compared to buying Charleston – Philadelphia non-stop].

When I went to check in online, the app and the website wouldn’t allow me and said I had to go to the counter.

Went to the priority lane, counter agent was pleasant even though it was 5:30am in the morning and he said I couldn’t check in online because he had to give me a warning about hidden-city ticketing. I played dumb and asked what that was and he explained.

He followed on to say that the warning is that they are watching me and if I don’t continue on to DCA on my flight this morning, I will be put on a list and I have the potential to have my Platinum status revoked. I just said ok and thanks and went on my way. Cancelled my flight to DCA as soon as I landed, and we will see what they have to say.

The reader uses hidden city ticketing regularly, it seems, and even when the savings are modest. And he attaches his AAdvantage number to the reservation.

• I recommend against using your frequent flyer number. Credit to a different partner airline. You can still be tracked, but why make it easier for the airline?

• This may be tempting to do when the savings are significant. I’ve seen cases where the difference is over $1000. I’d give it a miss over $25.

American warned him not to drop the Philadelphia to DC segment, and he did anyway. He assumes American will take his elite status and his miles. I’d have recommended flying to DC and then flying or taking the train back to Philadelphia, and cooling it on hidden city tickets for awhile, after being confronted by the airline.

The New York Times’ Ethicist said it’s ok to do throwaway ticketing. The late Supreme Court Justice Antonin Scalia did it. But there are risks.

United Airlines threatened to trash the credit of customers who skip flights by sending them to collections. Lufthansa sued a passenger over it.

If you’re going to use hidden city ticketing, here are the key things to remember:

• Don’t check bags, they’ll go to the final destination on your ticket not where you’re getting off
  
• Don’t put your preferred frequent flyer number in the reservation, an airline can shut down your frequent flyer account
  
• Be prepared to explain the need for your original routing in the event of flight delays and cancellations
  
• Don’t be the last to board – you don’t want to have to gate check your bag
  
• Only drop the last segment of your itinerary, otherwise the rest of your flights you do want to take will be cancelled
  
• Don’t do this super regularly where you’ll attract unwanted attention from the airline

Finally, you may be able to do this completely legitimately if you have your tickets issued in Italy.