True, but sometimes when people do seemingly stupid things it is simply ignorance or inexperience, not greed or malice. The proliferation of lengthy T&Cs (the "fine print") written in legalize in every aspect of modern life leads many people to simply not read them, and most of the time it works out okay for them. Then there is the misleading terminology used by UA employees when referring to MP benefits -- I often hear the word "free" used in connection with upgrades or flights, usually as a way deprecating the value of a benefit when something falls through.

We at FlyerTalk are unusually clued in to FF programs but I'll bet even we don't always stop to appreciate the monetary difference between a "free" mileage redemption and the list price of that benefit. A breezy approach to the matter might lead a customer to assume either something has no specific monetary value ("free") or else has been earned and the value belongs to them to do with as they please. Ignorance is no excuse, but it is the starting point and in my experience is more common than common sense.