I live 100 yards away from an elementary school. Each morning frantic parents pull up and park their cars in front of my house to deliver kids to school. The precious children impose an externality on my household. The kids and their drivers stomp on the nice plants we have planted in the soil between the street and the sidewalk. This is a fairly large rectangle measuring perhaps 70 feet by 10 feet. In the name of reducing our carbon footprint, we pulled out all of the grass and planted low water "cute" plants. To our surprise, the soccer moms and dads and their great children appear to take pride in stomping on our plants. I caught myself getting ready to pick up an 11 year old today and tossing him. The parents are worse. They lie as they "apologize" and then do the same thing the next day. I am tempted to cut their tires. This would be an accident of course. In Los Angeles, I do have a secret goal of becoming rich as I star in the new reality video series "Professors Gone Wild".
There is an interesting property rights issue here that keeps popping up. The LA Times wrote this about this issue.