The job keeps her active -- she can't even guess how many miles she covers each day -- and exposes her to all kinds of people and stories.

CNN: No flight to catch: A glimpse at airport employees, culture

Just how many miles get canceled is "proprietary" information that airlines say they won't disclose.

WSJ: Saving Frequent-Flier Miles From the Ax

Customers would also have to be informed how many seats were available for purchase with frequent-flier miles -- carriers haven't made it easy to compare one frequent-flier program with another.

FORBES: Fact and Comment