Grinders are on display for sale during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. The three-day event includes exhibits, evaluation services, legal services, equipment, and accessories. (Photo by Kevork Djansezian/Getty Images)

Sensi Pearl, an adult entertainer also known as Ganja Goddess, walks the convention hall during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

A sign warns convention attendees during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Scott Stansfield, a homeopathic doctor from San Bernardino, California, looks over a hydroponic grow cabinet during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Sam Khalil sets up pipes in his booth during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Convention attendees wait for a medical marijuana evaluation at a booth during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Models pass out free bags during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Bill Graham looks over a hydroponic grow with LED lights used for indoor gardening during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)

Marijuana activist Richard Eastman signs a flag showing a marijuana leaf for Penny Chan, from Long Beach, California, during the HempCon 2011 Medical Marijuana Expo at the Los Angeles Convention Center on August 26, 2011 in Los Angeles, California. (Photo by Kevork Djansezian/Getty Images)