That's not entirely accurate.

The companion certificates can be ticketed at any AS/QX ticket counter location or through any travel agent as well. These are the preferred option for the majority of customers. Mailing your coupon in with payment for both tickets is a last-ditch alternative for customers who cannot make it to either a ticket counter or travel agency (such as people who live out in the bush communities in AK, several hundred miles from the airport or the closest agency). It's not an option that is available to everyone.

Plans are in the works to have the companion certificates available for use through reservations and/or the website, however.