@SevenDad, says that by the time of the second kid, you loosen up. Agree, and then the third kid comes along and it’s like, yeah, whatever. Every once in a while I find myself semi-appalled by what I let the third kid do, but then I just shrug.
Not to state the obvious, but a kid is already exposed to those activities at boarding school. Going to a concert is not going to apply any more peer pressure than already exists.
As others have said, I think it really depends upon who the acts are. Most singers/bands that appeal to teenagers are pretty innocuous, although there are obviously exceptions.
I must start learning about pop cultures too so I can tell the difference between artists. 
All her life we listened to classical music only. But one day she got a smart phone with Apple Music. And everything has changed!
I’m reading this thread with great interest, and have determined that I am, in fact, the worst mother ever. With only one child, I totally skipped the 1st and 2nd child mentality and went directly to the 3rd. I haven’t known exactly where he was for most of the summer (although I had a general idea), and next summer when he has a DL/car, it will be even worse. But he’s a good kid, everyone knows him, and I trust him, so until he proves me wrong, he can do pretty much whatever he wants.
I have taken my D to her first 2 concerts this summer (Selena Gomez and Demi Lovato/Nick Jonas). There were lots of little girls there and I wasn’t worried about drugs or sex in the concert venue. On Friday I am going with a friend to a Pearl Jam concert to recover, LOL! I did secretly enjoy the Selena Gomez concert but not the other one.
@gusmm2000, I think we may have been separated at birth. Hubby would ask, “Where’s kiddo?” I would shrug my shoulders and say, “Probably playing in the street.” Best testament to my motherhood is a meme my boss texted me yesterday. It’s a woman and a little kid sitting in chairs across from each other:
Woman: Do you think I’m a bad mom Jimmy?
Kid: My name is Jack.
I congratulated him on his self-restraint for not photoshopping my son’s name in the photo. Guess I have a bit of a rep.
Cheers! 
I’ve always said that @ChoatieMom was my mom separated from me at birth, but I think @gusmom2000 is now going to give her a run for her money. So far, I think I’ve turned out OK. 
I don’t understand what you think will happen at a concert? A kid who has always acted one way won’t change all of a sudden, smoke crack in the parking lot and have sex in the rafters. People go to concerts to have fun.
You know how teens learn to make good decisions and become thoughtful and responsible adults? Their parents respect them. Their parents let them make their own choices. Their parents talk openly and honestly with them- “I hear there is sometimes some drug use at concerts. If you see any around you, what do you think you should do?” “You know you can always call us if you are out with friends and anything makes you too uncomfortable.” Etc. Be honest about your concerns, listen to your child’s thoughts and ideas, and let your child decide. If your child can talk out tough decisions with you, (s)he will probably make good ones. If you make decisions for him/her as the family autocrat, you create a tempting ‘forbidden fruit,’ you foster rebellion, you close off conversation between yourself and your child, and you deprive your child of an opportunity for growth through a thoughtful conversation with you and an opportunity to try out some independence by going somewhere with friends.
We talk a lot about alcohol, drug and smoking. She even knows that I would be lenient toward light alcohol, especially since we lead by example. So far her maternal and paternal grand parents all have worked hard but failed to convince her to try.
Pop music concert is something I know very little except some very negative images, and she knows very little too since she has never been in one. We only recently started to go to movie theaters instead of operas, and I don’t mind sending her to a movie theater, or a book store alone. Sounds like some artist’s concerts are pretty safe too. I think I would feel safe now to send mine alone to those as well.
@SculptorDad I think there is also something to be said for the company the kids keep. DC has a great, albeit small, circle of friends and I trust these kids to help each other when they are out and about. They are a goofy bunch for sure, but have similar goals and upbringings and so far have made good choices together. Safety in numbers, that sort of thing.
Especially when kids could drive, our rule was that we wanted a text upon arrival and when departing from a location. (Distances usually involved at least 30 minutes of driving, so this helped allay our concerns when there was no communication. ) We always made it clear that we would happily come get him from any situation that got out of control. Sensible friends help, but with kids this age, it’s also easy for things to spiral. A trustworthy kid can go with others to a situation that is not what was expected with no way to leave. So we were permissive but wanted him on our radar.
Can’t help but chuckle at this thread. Isn’t sending kid to BS pretty much the pinnacle of “independent activities”?
I was just wondering the same thing, @TheStig2, and then wondered if all the time I’ve been reading and participating in these threads if Prep School Parents was not merely focused on the boarding schools. Guess it’s not called Boarding School Parents…
So maybe it should be "how do you manage the permissions? "
As I read the comments above and agree that some might be more appropriate for a general parents forum, it strikes me that while kiddo is independent at BS, the rules are those of the school. When they come home, it feels like there’s not a lot of reference points for these decisions. And when they want to do something like go away to the beach for a week to someone’s house (without adults) with their BS friends, it’s hard to know what kind of company they’re keeping.
And yes, before freshman year, I was confused about the permissions. Wasn’t sure what I should be saying yes to.
That scenario is a no for us for now; someone, if not all of them, should be 18 I think. I grew up about an hour and a half from a spring break hot spot and wow did some crazy stuff happen even when we had someone’s mom along. The kids that were there without chaperone went pretty wild. Those memories are what give me pause. Maybe I will change my mind as AppleKid gets a little older and has some BS experience, but right now it’s a no.
Along the lines of parent chaperones, how connected do boarding school parents get with each other for purposes of trusting your kid to go off with them? Are there differences between day and boarding parents? Of the three sets of parents of kids going to DC’s school next year that we have had some connection with, we would feel comfortable with DC traveling/staying over with them. But not so sure about kids whose parents we’ve had no contact with at all.
@AppleNotFar , welcome to the world of “we’ve never met, but I understand that. …” conversations about plans that are often complicated. And given the different backgrounds of the kids, a weekend in Brooklyn could raise one set of concerns for a family from an urban area and a different set for the parents at home in Iowa. Our school did give parents the option of agreeing to certain rules for their homes and their guests, and you could then know if your child was going to a “safe” house,
I participated parties in high school. At beaches, someone’s house without adults and playgrounds at nights. I do NOT want my daughter to be do the same. There are areas where I want my child to have different experiences than I had, whether or not I enjoyed those experiences.
My guess is that BS kids will generally experience less of those than local private or public school kids.
@AppleNotFar having had multiple kids attend boarding school, we maintain the same communication with parents of their friends that we would have if they were home. A few examples: our youngest just attended her first concert with one of her boarding school friends. The other mom and I spoke by phone and reviewed their plans: where they were staying in NYC, the fact she was attending the concert with them and staying with the while they wandered the city. Same daughter just got back from visiting another boarding school friend in DC. The mom and I spoke via phone about the flights, activities etc…
As we now live close to the kids school, we have hosted boarding school friends at our home. Some parents reach out and some don’t. I hosted 6 of my sons friends on grad night a few years ago. Not one parent called to check on the plans.
The bottom line is you get to maintain your preferences as a parent even while they are at school for activities