I heard this story on NPR yesterday morning on the way to work. They treated it wittily, however, there is something disturbing about treating knitting as graffiti.
'Midnight Knitter' Wanted In N.J. Shore Town
The story is here: http://www.digitaljournal.com/article/288919
From the story: "A person or group calling him/herself "Salty Knits" has claimed to be behind the colourful handmade decorations that show up overnight. There is a Facebook group for the 'mystery knitters who are sick of knittin kitten mittens.'"