Have you ever talked with fundamentalist? It's not only plausible, but those adults have probably done the same thing while actually being serious about the preaching part in the concert
Yes! I went to an evangelical church run private school. They had the brilliant idea to send good "strong Christian" students to raves and parties to narc on their classmates that attended said raves and parties. I wish I was making that up.
Damn. I went to Jesus school from first grade all the way through high school. Doing something like that would have been a real quick way to get your ass kicked into a Jesus loving grease spot.
Depends on the town. Some of the ones in the Bible Belt? Absolutely possible. In others it's completely possible they knew the kids were lying and decided it was fun to play along and get them to a concert.