For years, savvy airfare consumers have used a trick called "hidden city" ticketing to cut the cost of air travel.
Here's how it works. Let's say, as a recent example, that the one-way fare between New York's LaGuardia Airport and Houston is $785. But the fare from New York to Austin, Tex., with a connection in Houston, is just $101. If Houston is your destination, then why not just buy the Austin fare and get off in Houston?
There are a couple of problems with this.
For one, it doesn't work with round-trip itineraries. If you book a New York-Houston-Austin-Houston-New York round-trip in the above scenario at $202 (twice the one-way fare), get off in Houston, and don't show up for the Austin-Houston-Austin-New York legs of the trip, then the airline will cancel all your remaining flights. And no, you cannot get around this by buying two separate one-way fares.
In other words, you can't buy a return Austin-Houston-New York fare for $101 because when you don't show up at the Austin airport your Houston-New York portion will be canceled.
The other problem is that most airlines prohibit this ticketing trick. Only Southwest, of the major carriers, has no language in its contract of carriage prohibiting hidden city ticketing. (Southwest used to specifically state in its contract that it had no problem with hidden cities, but a recent perusal of the rules merely reveals no mention of the practice).
No, the airlines will not throw you in jail. But if you do it too often they might kick you out of their frequent flyer program, confiscating your miles. And if you buy a fare through a travel agent, they might go after the agent with a "debit memo," charging her for the fare difference.
So don't buy hidden city fares through travel agents and don't hand over your frequent flyer number, travel hackers advise.
More worrisome, sometimes the best laid plans of fare hackers can go seriously awry. What happens if some portion of your New York-Houston-Austin flight is canceled or delayed and Continental decides to re-route you through Cleveland and then onward to Austin? Sorry, pal, you're going to Austin after all, or, at the very least, Cleveland (that, or you can just kiss your fare goodbye).
But hey, we hear Austin is a fun place to visit.
George Hobica is a syndicated travel journalist and founder of the low-airfare listing site Airfarewatchdog.com. Follow Airfarewatchdog on Twitter @airfarewatchdog for late-breaking unadvertised airfare sales and air travel advice.