A good yarn or weave got working together

Yarn bombing is popping up everywhere, we enjoy seeing lots of examples on File Tag Ville on Facebook, and this week on a  visit to Nottingham I saw the remains of a recent display there.
Now I've just read that last March in Leicester it was used in a campaign to cut down fear of crime - the idea is that people feel safer when they pass through public areas adorned with pom poms and the like.
In the article on the Leicester woolly campaign, Sgt Simon Barnes says that people's perception of the level of crime in the areas of Bede Park and Great Central Way is in fact different  to actual reported levels of crime but that activities like this increase community engagement, making people feel that the area belongs to them.
Some members of the public weren't convinced, but that's just their initial reaction, only time will tell.
So what is it, woolly headed liberal optimism that a spot of colour can change things, or a genuine attempt to create a close-knit community?