How about this, let them be until they break a rule here that compromises the safety of themselves and/or others. Revoking AV status should only be considered then and not on the grounds of drug use. If they are are going to be stupid and go shoot up, smoke or whatever in their car, you can try calling the cops. Whether or not they will come is a different story. One issue I have will be with blatant illicit use of drugs around minors and I will not stand for that. Many games will be at PB fields and there will likely be minors around.
If you're going to use drugs, go be stupid in the privacy of your own home.