There are some questions about how the law will be enforced. I really don't think this law was enacted to actually stop people from smoking in public. What the law does, is give non-smokers power over smokers.
As it is, when I'm walking down the street, or waiting for the bus, or whatever else, and someone lights up, I am the one who has to accomodate to them, because they have the freedom to smoke, and if their freedom imposes on my freedom to not smoke, then to bad for me. However, if I were living in Calabasas, I would have the power to tell the smoker that he is the one who has to accomodate my needs, and if my freedom imposes on his freedom, then too bad for him.
Of course, it is a bit of a bluff, because it is unlikely I or anyone else would actually call the police so they can ticket someone for smoking.
The law also serves as a stepping stone, as it said in the article, <div class="FTQUOTE"><begin quote>Supported by the American Cancer Society, Heart Association and Lung Association, the Calabasas ordinance follows a landmark January decision by the California Air Resources Board to classify second-hand tobacco smoke as a "toxic air contaminant."</end quote></div>
I think this is the main reason the law was passed.