ok.. so let me try this again..
If someone is at an airsoft event and they are under the influence of any "mind altering" narcotic then it is my opinion that they should not be playing that day.
If said person decides that they can play "under the influence" therefore affecting the safety of other players, then "yes" I wold love there to be an entity out there such as ASC that could enforce a zero tolerance rule, however realisticly, I understand why they can't and more than likely will not. So it will inevitably be the responsibility and at the discretion of the host/field owner.
MmmmMMmmm, Dinner. Fits perfectly between work and drunk! - Homer J. Simpson