Originally Posted by LuckyTarget
I have to disagree with all of the above.
Nothing will happen - PERIOD!
As stated by Techgirl - the ONLY time the airlines have any recourse and may, and that's the magic WORD - MAY follow up on this is when it's done on a regular basis, and the only time I have ever heard of a follow up was when a TA was sued by NWA couple of years ago for doing this for his clients all the time and actually suggesting/recommending this. To be honest with you, I'm not even sure if NWA won that lawsuit. On an individual basis, doing it here or there, NOTHING, and I will guarantee it!
I'm guessing you have never had your FF account suspended and have lost all of your miles for doing this, have you? I know two people (one posts here) who have.
We also had a throwaway ticketing thing going at our office for a while where our agents were booking us on circumvented routings to keep costs down. At the time, a 14 day advance DFW-SEA/PDX/SFO/SJC/etc. flight on AA was running over $1000 (about four years ago) and AUS-SEA/PDX/SFO/SJC/etc. was running under $300. We would buy two tickets - DFW-AUS and then AUS-other city (usually back through DFW). So a ticket to SEA might look like DFW-AUS-DFW-SEA-DFW-AUS-DFW. Legal ticket. My colleagues were stepping off in DFW and not flying the last two legs (i.e. the last segment on each ticket). Over a one month period of time, someone from AA met several of them at the gate and told them that they could either take the DFW-AUS-DFW flights or be subject to AA re-faring the tickets.
So... I speak from near first-hand experience that AA will go after passengers for this. They won't do it the first time... but its also not something I would do more than once or twice without some hesitation.