Originally Posted by
Antarius
Say OP bought A-B-C and only flew A-B. Lets leave the cost of A-B aside.
AA would not have been able to sell B-C as the ticket was tied up until departure. Therefore quoting your post "can easily show damages there as they can no longer sell that item"
They already did sell B-C. The OP bought it. They just didn't get the opportunity to sell it
twice.
If one really wanted to pursue some sort of moralistic argument against HCT, you could say that the act potentially deprived someone who really needed to get from B to C the opportunity to do so. Outside of this coronavirus period, with many full flights, it isn't an entirely hypothetical argument. It's the same reason I believe that overselling flights, within the scope of a strong, clear, well-enforced passenger bill of rights, could continue in a fair/ethical manner and benefit both passengers and airlines.