The Spanish town of Brunete, near Madrid has come up with an unusual solution to people who let their dogs do their business in the street. Volunteers chatted to offenders (people, not dogs) to find out details that would allow their dogs to be traced via records. Then the offending matter was returned to the owners who’d left it behind. A simple social change idea put forward by advertising agency McCann. Which has, allegedly, led to a 70% fall in offending.