How and Why Does This Happen?
Why would anyone waste a perfectly good pair of shoes?
This is on the corner of Fore and Cross Street in Portland. There they were up on a wire. This is a thing, but truly why?
According to Wikipedia:
Shoe tossing, the act of using shoes as projectiles or improvised weapons, is a constituent of a number of folksports and practices. Today, it is commonly the act of throwing a pair of shoes onto telephone wires, power lines, or other raised wires. A related practice is shoe tossing onto trees or fences. Urban legends tell that the shoes represent the location where a gang murder or hit took place. In urban areas, it can serve to signal that a drug dealer is nearby or one can purchase drugs in that area.
Nevertheless, the main reason for dangling shoes on high wires is for recreational or trivial purposes, usually as a prank played by bullies and drinkers. Thrown shoes may also symbolize local culture or traditions of some sort.
A prank by bullies and drinkers. I'm going with that instead of the whole gang thing.