We did it a few years ago since it was a departure from DCA and really just started our vacation later but we were going to stay with friends v a hotel so had the flex. We countered with $750/pp and the American airline girl could have kissed me

they were j think at $400/pp at the time. DH and always joke we should have led with $1k/pl and negotiated down lol
It was so funny because they ran the oversold again in our later flight but by then we were ready to holiday
The upshot is we ended up booking 2 trips each with the funds in American and it got yo the point where we were tied to American always seeking flights since it was a great deal for us at the same time really hating the airline because both those trips had so many issues on AA! So in hindsight we weren't unhappy we saved money but at the same time wished we got more out of it, booking one big trip using the funds. The moral is the money is nothing to them because they can always get that back in profit. You're tied to using them again