They are gang symbols!!! It's been that way since the '70's! Don't mess around anywhere you see that! I don't care what anyone else tells you, that's what they are! I have numerous family in law enforcement! Gangs mark their territory in many ways, the shoes are one, tagging buildings & signs are another!
As a kid, I would see gym shoes and Army boots on power lines all the time. Being from a military town, I was told that it means that someone just got out of the military. It's suppose to symbolize "hanging up your work boots" and moving on to a new chapter in your life.
When I was in the Army in Germany my extra pair of combat boots where tied together with their laces and a piece of copper wire 3(the wire the biggest that could go through the eyelets) was used to to hold them up longer. When I was ordered back to the states, on my last last day in Wildflecken, West Germany my boots were thrown over the wire to leave a piece of me behind on the other side of the world.The people that I worked with knew every time they looked up at the wire and seen my boots that a piece of me was there with them.
The world's going to end. Just kidding. It means some dumbass decided to throw ther shoes on a power line. could represent something of importance, but I've never heard of anything. Drugs are bad kids.