Oh, I just hate this. I am very anti-grafitti to begin with. People who use their time and resources to make the world uglier for everyone else are kind of shitty in my book. Now folks have a tool to do large scale uglification at low risk to themselves. You can argue six-story advertisements are a blight on society, and I would agree with this. But spray painted advertisements are even worse, and I don't think vandalism is a good way to fight against this assault on our attention. I doubt that few graffiti vandals have such lofty goals in mind anyways. Drones with cameras can also now easily float outside of windows, high up apartment buildings, and spy on people in places where they have a reasonable expectation of privacy. The world is changing in mostly good ways, but I see a lot of potential for drones making the world a worse place in which to live.