Although the mandated rule that marijuana dispensaries in the city of Los Angeles must not be located within 1000 feet of places in which children congregate has good intentions, it is not practical.  When examining the geographic elements of the question, it becomes clear that very few schools are in fact located within 1000 feet of the majority of marijuana dispensaries in the city.  A law, therefore, preventing the establishment of medical marijuana buildings would waste funds shutting down on a few marijuana locations.

 Additionally, it should be noted that the majority of these marijuana dispensaries do not promote themselves and do not intend to draw in children.  Many of these places are inconspicuous and unlike the tobacco industry, do  not rely on advertisements in order to gain revenue.  These places are in no way targeting youth, as shown geographically in that they do not intend to locate their establishments close to schools, and therefore, it should not be an issue as to whether or not they are within 1000 feet.  The issue of marijuana exposure to children is not a matter of the location of these dispensaries, more a matter of the prevalence of marijuana and if the city really wished to prevent the exposure, they would outlaw the dispensaries all together.  Making a small, useless legislation will not change whether or not children are exposed and can get a hold of marijuana, it will, once again, only waste the city’s money that should be going to schools anyways.
Also, elements of this law do not make sense and prove that it is not a well-thought out law and would again, wast the governments money.  It claims it aims to end the late-night life promoted by the dispensaries and make them shut down at 8pm, but this does not have anything to do with schools, since schools are not in session at this time anyways.  This therefore would increase traffic during school hours, actually going against what the law intended.

If, however, the Marijuana dispensaries continue to expand into areas that are increasingly nearby places in which children congregate, governmental action should be taken.  Since however, it is clear that they are not geographically nearby it would simply be a waste of money to implement such a law. 

References:

UCLA GIS Mapshare

Census.gov- TigerLines

maps.google.com