You also have the issue of exactly when is a ticket "unused" such that miles could be awarded? Certainly, not right after the flight was missed. On certain fares, tickets can be reissued for up to 1 to 2 years from the original date of issue, depending on the fare type. Most fares can be reused later as long as you cancel the original flight reservations before departure. So, they'd have to have some complicated way of keeping track exactly when tickets expire in order to award miles. I doubt this is worth it for them or for the passengers.

[Edited for spelling]

[This message has been edited by Steve M (edited 09-26-2003).]