Today, the City of Los Angeles will begin enforcing its ordinance regulating storefront medical marijuana dispensing collectives.  The ordinance will force most of the city’s collectives to shut down (over 400 establishments), while the remaining 138 or so (those who registered with the city prior to Nov. 13, 2007) will have to comply with new zoning laws that are stricter than those for adult entertainment businesses, retail alcohol vendors, and pharmacies. I will be the first to acknowledge that…