That's a great statement, but nothing about it is (or, more accurately,) should be necessary. The pilot in F is not operating that flight. The pilot in F in on his way somewhere to operate a flight. Thus, one of two things happened: either AA already knew the pilot would be on that flight and upgraded (or sold) a seat they shouldn't have, or AA failed operationally by not having that pilot where they needed them, when they needed them, thereby creating an emergent situation where a downgrade is necessary. Either way, it shouldn't be necessary, and AA failed somewhere. I don't fault the pax or the pilot, I fault the airline (any of them) for being stupid.