Trainers on the Lines

Its reckoned that throughout the world there are now millions of trainers/shoes hanging from cables etc. 

There can often be a meaning like gang territory, or drug dealing.  Or sometimes its just a case of bullying or vandalism. 

In this case I would have guessed possibly the drug connection but the fact that there are so many of them - several more closeby - I think they are just having a laugh!  (But not so funny if your trainers end up there).