I'm not interested - I don't want to do anything that would jeopardize my relationship with a credit card issuer (besides opening and closing cards until they get tired of me), and this seems pretty shady.
Plus, I already get at least 1 cent per mile/point, so I don't see the value of doing this.
If I'm not going to use a particular airline, I just don't sign up for the card. I focus my efforts on the cards which actually bring me value. For example, I never fly Southwest because they don't service my local airport, and therefore I'm uninterested in their cards. Some programs have approved means of transferring their points elsewhere - I think redeeming AmEx member rewards for a statement credit is a poor use of the points - but booking flights through them, or transferring to Delta or British Airways gets you a better value.