This looks like an old thread but I will chime in with my experience. We had flights scheduled in May DCA-PDX in F class. We used money and miles. Recently I found out I was going to need some extensive back surgery and would not be able to travel anytime in the immediate future, actually, maybe never fly again. I secured a letter from my surgeon and submitted the information to Delta. They very generously refunded all of our money back into our credit card account and the mileage back into my mileage account. No fees charged. And they were non-refundable tickets. So I have nothing but good words to say about Delta. They came through and went above and beyond what they had to do. They will always be our airline of choice (assuming I can fly again.). It is nice to see some companies will do the right thing.