"Time to hang your boots up"

There are various theories to explain why pairs of shoes are strung over telephone lines.

Among the reasons are;

Drugs are available for sale in the area. Recreational rather than paracetamol.
When a new pair are aquired the old pair are dispatched over the wires.
Designated gang territory.
A murder has been committed nearby. Good grief.
A time honored tradition on the last day of school.

There are many more ideas but I think kids are pesky and simply like to do it.