[nostromo]

As much as I'd like this to happen, I bet they would sell fewer tickets. A certain number of travelers sort ticket results based on price. If they added even just a few dollars to each leg to pay for perks, they would push themselves down on the results page and sell fewer tickets.

[awa]

yes! Wanted to say exactly that. Esp. with aggregate sites like kayak, priceline etc. this will push them lower in the results