Usually there's a local story behind things like this.
I used to live on a college campus where they did it to powerlines, annoyed the maintenance people to no end.
Though I like to think of this one as being a community of slow people, they tried to hang themselves but didn't know how to do it right.
I know there's some urban communities where the shoes over the powerline is a signal for "buy your drugs here", but this shoe tree is a different animal; it's intentionally drawing attention; I'm curious as to why.
