A group of US Peace Corps Vounteers decided to act out an anti-littering message on buses operating around San Miguel. Watch their video.
According to the PCV who pointed me to the video, they were well-received:
Reception was pretty good - we'd sit on the bus afterwards for a while, and lots of people would ask questions about who we were and why were doing this. Some people put trash in Jesus' bag when he went around. On some of the buses people clapped and cheered when we finished.