Originally Posted by
vincentharris
I am confused on how if you do not call them to tell them to cancel it you are at fault. I have flown before then changed plans and driven home etc and just didnt bother flying the return flight. Never had any problems.
This.
Don't call and cancel - just don't show up for your return flight. This way, you don't have to explain anything to anyone. Any credits due will automatically be put in your DL "wallet".
Yes, you are gaming the system but you can usually get away with it once. If you do it repeatedly, the DL revenue protection unit (the infamous RPU) will notice and take action.
Also, if you are a non-US citizen, make sure your non-returning does not violate any immigration law, which could be a MUCH bigger issue.