How does AS key in requested credit?
 

I recently flew one way XNA-CVG-MHT on DL. After boarding my first flight I realized I forgot to provide my AS# at check-in. When I arrived home I mailed in a boarding pass along with my itinerary which referred to XNA as "NW ARK REGIONAL". I just checked my AS account and i received credit for EWR-CVG-MHT. I can see the easy mistake there (NW ARK vs. NEWARK). Actually it looks like I benefitted by about +9 miles, but if they're not using the actually reservation numbers, and instead just reading a printed email itinerary, it would seem this would leave the airline open to fake claims. Any thoughts?

They more than likely do not have access to the specific reservation on the partner carrier, so this is why boarding passes are required for this. This was simple human error. For a 9 mile difference I wouldn't go forward with it; its more hassle than its worth.