I personally don't know anyone who informs or lets their child participate in their drug-related activities...I think that's pretty fucked up, actually. Kids don't know better, kids don't know how to make choices..... they just know what their parents know, and soaking a kid in drug culture before he/she can choose differently, seems kinda...icky. And not a good way to raise a kid that'll have some hope of fitting into a "normal" society (well, you know...something besides the drug culture).

I applaud your decision to keep your kid away from the drugs- I mean, you can't shield him forever, but by going there and letting your friends openly drug themselves in FRONT of him...that's like saying it's OK. And it doesn't send a good message to the kid, when he'll hear most everywhere else that "drugs are bad, mmkay".

I can just see it now. "But Mr. D.A.R.E officer, all my mommy's friends say pot is great!"

Not knowing much of anything about your or your child besides what you mentioned, I took a big clue from this sentence " I did explain to him why we were not going and he got it and agreed. "
It seems like you are one of those amazing parents who treats their kid as someone with independent thoughts and emotions, with respect! Kids can and will make their own decisions, especially when you aren't looking. At 8 years old, the parents are still the main role models. They will certainly be curious about what other adults are doing, but I think that if you explain your point of view in understandable terms, rather than letting the child form his own possibly fallacious conclusions, the situation is relatively safe.
Being in lung shot might still be an issue though. Can't really rely on other people to be as responsible as you are.
There's also the possibility of some of these situations becoming a negative example. My cousins grew up in the whole Humboldt county, reggae on the river, kind of environment, and they're both pretty repelled by drug culture as adults. So who knows.
Bottom line is that talking to your children openly and honestly is probably more helpful than limiting their exposure to situations. It sounds like you're already on top of this.

I think you did the right thing about ROTR. In my experience in the past these events are fun but not really the family type place. Dont feel bad about making your decision to protect your child from drugs. Everyone parents differently and there is nothing wrong with the way you parent. I would do the same thing. I know that one day my kids will be exposed to drugs (when I have them) and while i want them educated I also dont want them experimenting at the age of 10.

kids don't just know what their parents know, as someone said. Following my parents' divorce, I was a child and spent too much time around adults much like many of the burners I've met. They had open marriages (not polyamory) and hid their drugs badly. As a kid, it was obvious to me they were destroying their marriages for nothing very important, and that they were stupid when they were stoned or drunk. I used to go out to the fields and hang out with dogs to avoid the people.

I don't think I would have cared much if we were at a musical event I was enjoying and the adults most directly connected to me were maintaining some kind of decorum. Being in the care of drugged out adults is not fun, because drugged out adults are self absorbed and sometimes a danger to themselves or others. Kids want to feel safe, cared for. But they also like to see a bit of the world. I don't know if it's harmful for them to see stoners/weed -- though it's plainly harmful for young people to feel that the people who are in charge of them can not be relied upon.

I remember being skeeved out by some of my parents' friends. You don't necessarily want your parents hanging out with the chick who grows dope. The chick who grows dope may leave you feeling kind of unsettled. I'm wondering if another option might have been to keep the dope-grower chick away from your kid, but go to the event separately and let your kid take in that some people in the world smoke dope, but that they are in a family that's not about that at this time.