Simple as this. As far as drugs are concerned they are illegal. Does not matter where you are. If I happen to be hosting a game and I find some one impaired by them they are removed from the game no questions asked. There is no second chance. If your stupid enough to show up to a place where the objective is to run around and shoot people and you think it's a good idea to be stoned then your not welcome. Im sure we have all had bleeders from the guys that are sober and alert the last thing we all need is a bunch of drunk/stoned players firing hot guns at us, never mind the attitude problems that are usually common those those types of players as well.
We harp on minors to be safe and smart about getting into airsoft but some times its the people that have been playing a while that developed bad habits that can become unsafe. Now dont get me wrong I enjoy a drink as much as the next guy and I did my fair share of drugs years ago but really, if you choose to do it now all the power to you, just please be responsible and do not do it at games or on the way to the games that every one else is trying to enjoy.