Originally Posted by
davie355
A better analogy to OP's flight rebooking is: what if I order california rolls, but upon delivery, I receive rainbow rolls, which are much more expensive. This happened to me yesterday. I just went ahead and ate the rainbow rolls. Did I steal from the restaurant? Was I dishonest?
This is where context comes in.
If you find a newspaper on a train you aren't expected to try and find the owner, or hand it in to lost and found. If on the other hand you find a diamond ring on the train you will be expected to take reasonable steps to try and find the owner (or hand it to someone who can).
With your mistaken rolls, by the time they were returned they would have been ruined. Fair call to consume them. That's not what happened with this ticket.