Hey Santa, what’s with the footwear fetish?

Hawaiian kids leave out their shoes for the Magi, stuffed with grass for the hungry camels. Dutch kids fill their shoes with hay for St Nick’s horse. American kids hang their stockings by the chimney so they can be filled with treats. So basically, all over the world there’s this bizarre ritual involving an exchange of goods taking place in stinky footwear. What the heck is that all about?