The 2010 Arizona Medical Marijuana Act exempts qualifying patients from prosecution, but most Arizonans are still subject to arrest for felony possession of any amount of marijuana.
Phoenix police alone arrest an average of about 10 people a day on suspicion of possession of marijuana.
Phoenix police arrested 2,972 adults and 600 juveniles on suspicion of marijuana possession from July 1, 2011 to June 30, 2012. That's nearly 3,600, or about 9.8 a day, each day of the year
Source: Phoenix New Times. Read full article. (link)