Anti-social behaviors to criticize anti-social behavior

Jan Chipchase's last post is about anti-social behaviours (of dog owners) "through actions that many other people would consider anti-social, even if it involves graffiting one's own wall reminds me a trend in Geneva: everywhere on walls, journal distribution cases, trash-cans... there is this message "PLEASE KEEP GENEVA CLEAN" or "LAISSER GENEVE PROPRE" (it's actually both in english and french). An example:

please leave geneva clean