An under 21 year old can go shoot up any substance - with the guarantee that the police won't touch them - at any of the safe injection sites, but progessive-heaven forbid that they want some whipped cream for their ice cream or want to try a recipe that included using one of these gas cartridges.
Canisters on the street? A disturbing eye sore that must be dealt with swiftly. Needles on the street? A sign of progressive tolerance and a reminder that drug users are the real victims.