Report Offensive Message

Ok. I see the accidental foot art innovation. What was the message that the foot traffic picked up beside the paint on their feet? In the States the artist would have been sued for damages by local businesses and pedestrian for damage to shoes, clothing and store floors. Besides that and the fact this author was suckered into writing about this street art, how effective is this in communicating any real messages. Again, what was the message? "Walk on trees, it makes them greener."