Damn, it amazes me that some people are making so much of this. I'm gonna guess that most who have a problem either don't have kids or don't have friends.
My wife and I have a large circle of friends with kids ages .1 to 5, and we hold craploads of parties and dinners and get-togethers and playdates and Rock'n'Romps and etc. At most of these (i.e. all of them), we might each have a couple beers/drinks over a couple hours.
Now, we're not playing 3-Man or pulling out the beer bong, but we're having a few drinks, and honestly, it's just fine and no one ever seems uncomfortable with it. (It helps we all live on the Hill and so walk to and from these things.) But even with the larger issue of drinking, I don't hide it from my kids. Hell, when my son has a juice box, he calls it his "beer". When we go grocery shopping, he'll remind me if we're low on beer and wine. Good boy!
I drank a SHITLOAD when I was young, starting at age 12/13, much of it because it was forbidden and my parents got SO worked up over it (it also made us sneaky about it, meaning we drove to places outside of town to drink). I'm not going to create that environment for my dudes. Teenagers are going to drink, the key is to be smart about it, and the more open you are, the less sneaking and lying that will happen.
These kid-friendly music things are fabulous because it's a chance to show the brood the kinds of things I'm interested in. I'm not looking to bring a 4-year-old to The Sword, but the idea of being around other kids dancing to music is pretty awesome. There might be pervs around, but I'll bet there's a helluva lot more of them watching us play at Lincoln Park than there are in a club.
And honestly, that whole troller-man part of the story was clearly made up, or mightily embellished because the writer wanted to be cute.