One theory is that it originated in the Tudor period in Britain (late 1400 to 1600 AD) when guests threw their shoes at the wedding carriage and if you hit it, good luck would follow you. At least you got to pick up your shoe afterwards. Perhaps the wealthier ones (and poor shots) decided to take chance out of the equation and tied them to the carriage to get the same result. The cost of shoes riding off into the sunset then led to tin cans being a cheaper option.