FWIW a friend was on a DL flight ORD-ATL once that turned back to ORD due to an issue in flight (oxygen masks were dropped). Because she was doing a one-day turn for meetings in ATL she decided not to go on the re-scheduled flight. She called DL & asked for original routing credit and got it (miles only, no $). Same friend had been on another DL flight ORD-ATL a couple years before that that had an emergency landing in BNA (no oxygen that time). She had changed her flight & lost her upgrade so was in the exit row...FYI even though they tell you the door is 35 lbs & might take some effort to open, she said when you actually do it in an emergency it's light as a feather! DL sent another plane to get everybody several hours later. I don't recall what she got out of that other than a really good story. She rarely flies DL any more.