Originally Posted by
TLVtraveler
Going slightly off-topic, coming from a legal background, I have never read any court cases of an airline trying to re-price a ticket for a skipped last leg and I think that if such a case ever reaches a courtroom it would be very hard for an airline to prove that any damages were done, actually in recent years EU legislators have discussed the issue of round trips and complex itineraries, there have been talks of regulating airline pricing strategies (for example forcing airlines to sell roundtrips at the same price of two one-way tickets).
The only valid claim an airline could make in court as far as I know is that by skipping a leg the customer may have caused a flight delay due to luggage having to be removed from the skipped leg.
There are some sanctions that airlines can employ without having to go to court:
1. Closing down frequent flyer accounts.
2. Potentially banning pax (won't be possible in the EU due to anti discrimination laws).
3. Obviously cancelling future legs of the itinerary.
4. Warning regular skippers that their actions are against T&C.
While you are certainly correct that the easiest way to deal with hidden city fraud is simply to shut down the FF account, zero it out and cancel any status, the question is not about damages, it is about contract.
How that would be handled will differ from jurisdiction to jurisdiction. But, in most jurisdictions, combining the contract you make when you purchase your ticket with the contract for your credit card, simply issuing a debit memorandum to the credit card for the difference between the fare flown and the fare due would be a simple matter.
It would then be for the passenger to sue the carrier to recover.
All of this is notional because while it is reported as a regular practice on FT, FT isn't the real world and not many people really do it. Or at least do it often enough for carriers to care. And then they care, punting them out of the FFP is punishment enough.