In the picture above, Bansky has created graffiti on the wall in Isrial that is more of a comical painting. He puts an image of "cut here" on the wall to motivate people to want to get through the wall. The reason he may have put it here is because the wall is a symbol of denial, and people should want to "cut" through the wall and get to the other side. Another reason the location was a good for his art is because the large amount of people that gather by it. In this picture alone, you can that there is least a hundred people who are gathered already. Everyone will see his work and remember it now.
In the picture, Bansky has taken WILL FINISH LATER.