For Ms. Stadlin, adopting the rule for Eden Village was an obvious choice. “This is good,” she remembered thinking. “This is powerful. This is magical.”

And campers, knowing that no one will comment, seem more willing to experiment with their image, wearing capes, ninja outfits or big hairdos. (Ms. Stadlin said that the other campers would engage with them by saying things like, “Oh, you’re wearing a cape, let me fly with you,” or “Tell me about your superpowers.”)

Rachel Steinig, a 14-year-old high school freshman from Mount Airy, Pa., who has attended Eden Village for three years and is attending this summer, believes that because her fellow campers can’t comment on her clothing, they focus on who she is as a person. “People really like me for who I am and not what I look like, and people actually pay attention to the sort of person that I am,” she said. “Your dress isn’t really you, it’s just something you bought. But whether you are a good friend, that’s truly you.”

At Farm & Wilderness, the rule is so ingrained in most alumni that many of them stop thinking it is something special or different. “It’s something that we’ve been doing for so long that it doesn’t seem like a new or a novel thing,” said Pieter Bohen, an alumnus and the camp’s president. “It’s just part of the way we operate.”

Ms. Stadlin also receives emails from parents, including Ms. Gould, saying that as a result of their child’s request, they have started the “no body talk” rule in their home.

“I think that if you are going to send your child to a camp like this, you are making a pretty conscious decision that it is important to you,” Ms. Binn said. “And I would imagine, at least for us, that you would try to take the focus away from that when you are in your home as best as you can.”