Police in Honolulu, Hawaii, recently sent out a letter to 30 medical cannabis patients warning them they had 30 days to hand over their guns. When medical cannabis becomes legal in Ohio in 2018, patients will not be permitted to own or possess firearms. Similar restrictions have been imposed in California and Oregon despite state policy, and they are not new.

In 2011, the Bureau of Alcohol, Tobacco, Firearms and Explosive issued a warning that because cannabis is illegal at the federal level, patients cannot possess guns. "There are no exceptions in federal law for marijuana purportedly used for medicinal purposes, even if such use is sanctioned by state law," the ATF said in 2011.