It sounds like we are talking about two scenarios. Not sure if both are covered by TIV:
Simple Scenario 1: You have a same day trip planned from A to B. While still in city A, realizing how delayed you are, you cancel your ticket without using it. This is just a refund of a nonrefundable. They sometimes call this involuntary refund;

(more complex)
Scenario 2: As above, you actually fly from A to B. Perhaps your delay was out on the field, and you could not get off the plane. You miss your meeting or whatever you planned to do in city B, and you want to fly home, plus get a refund or credit for the trip since while indeed you took it, it was in vain. I don't think the people that invented trip in vain considered mileage runs .

The first scenario is very easily accomplished, but the second is perhaps more complex?

One time on CO years ago this happened. I was flying BOS>EWR>DCA. I did not get on a connecting flight in EWR and I would have ended up in DCA very late. So they sent me back to BOS, and wrote out handwritten ticket coupons for future date travel
BOS>EWR>DCA and returning DCA>EWR>BOS. I suppose this was an example of a trip in vain, but the agents never used that term or any kind of jargon to themselves when doing it, and I even got a print out of that PNR and there was no jargon about it.