Illegal Graffiti Picture

Found this on a blog a few minutes ago. I'm still trying to figure out if this a statement about the illegality of graffiti, whether the artist's name is "illegal," if it's just the start of a bigger piece, or maybe something else I haven't thought of yet. It was done by an Oakland protester from an #occupy movement there. Note the anonymity of the artist and his/her wearing of all black. Any thoughts of the significance of this image and why the Wall Street Journal is featuring it on their site?

http://blogs.wsj.com/photojournal/2011/10/27/photos-of-the-day-oct-27-2/

Hana