Could you not convince your local organizers to opt for a stronger stance against weed and alcohol at games? That would seem more logical than trying to turn the public trading square into an execution platoon based on an ideology that's often debated.
Owners and organizers can state explicitly - no drugs or alcohol on the field - if they're against it. If ANY explicit game rule is broken, by anybody, that person should be taken aside, informed of the rules and expected not to do it again. If that person consistently breaks the rules, then he/she can be banned from games/fields by the owners/organizers. Any more policing and you're turning this into a witch hunt.
Similarly, if that person breaks ASC rules, then he/she can be banned by ASC. ASC is a trading post where games are announced and hobbyists gather, not a regulatory body. It has no authority on the field.