NW did this and it made us feel they cared about us as folks who fly every week and pay them big $$$. We had the impression DL doesn't do the same as they seem to view frequent fliers as more of captives in NYC or ATL - perhaps we're wrong... Honestly the 2 or 5K miles doesn't make up for the foregone revenue from missing real business, but that small gesture makes a huge difference and had kept us and our travel buyer loyal.