Comment Re:doesn't matter which way court case goes (Score 1) 126
The airlines will simply insert a clause in the purchase agreement that says they can dock you the difference if you don't show up on the second leg.
That is very unlikely to survive a legal challenge, because although statistically people doing what you are doing may be costing them money, (difficult to prove, but plausible) they would have a very hard time proving that not providing YOU the service caused them additional expenses that requires recovery.
Just because it's included in the contract doesn't guarantee it's enforceable.