I really do think this is a cute idea -- it would show people some monetary value to using their local libraries. Academic libraries could even use this as a way to tell students -- SEE! look where those student libraries fees go! Now just calm back down and go back to facebook. Of course I also joked that some folks may take it as an opportunity to sell library books online -- "These 5 books are worth $400?!? w00t! Look out intertubez heres I come!"
But I also think this xkcd comic kind goes along with yesterday's conversation -- I mean you don't have to worry about this at the library. ;-)