To pull off the stunt DHL used thermosensitive paper to cover the boxes. So when they were loaded on the truck cold they just looked like big black boxes. Later when the workers carried then around the street to deliver them they were proudly displaying their clandestine message.
It doesn’t look like they tried sending any though the post office. If they did I’m pretty sure they would have ended up in Federal prison. I doubt postal workers look kindly on color changing packages. Although I would have like to see the bomb robot come and destroy it. That always makes for a fun afternoon.
Hit the jump for the video.