In my town, a pair of sneakers dangling over the telephone wire means you're on the right corner to make a quick drug deal--no lie. It's cheap advertising and eventually the laces break and the shoes fall down. Ymmv.
There are many myths like indication of a dead person , selling of cocaine etc but the real answer is known by the person who hang shoes on power line.
shoes is the bad conductor of electricity. It will help to prevent from electric shock to our human body. The electric shock will come mostly when the human body touch on the earth. But our shoes prevent it.
