I think PineyBob has an excellent point. FF programs have the effect of building a relationship with a person, not a situation.

Maybe a person's current situation is that they work for a company whose policy it is to pay discount fare for travel (I work for a company of three people and a cat - I know what it's like). But all sorts of things can happen. People change jobs. The economy changes. New business interests far away. All sorts of things. I suspect that for many it is cyclical. They trade their loyalty to me (in the cheap times) for my loyalty to them (in the good times). If they were only loyal to me when times were good, I'd go somewhere else as soon as times were bad (and probably stay with them). People don't like to be slighted and will go somewhere better if they are.

- cheapo