No matter how "enlightened" people get, spraypainting something on another person's property is a crime, no matter how pretty it is. If i was a "car keying artist", would you have the psuedo-progressive attitude twards a piece of artwork I scratched into your car's paintjob? I am an artist, but i also respect the fact that alot of people don't want me painting stuff on the side of their house. Its called being an adult. The reason that public art walls never work that well is the fact that most of the taggers are just vandals