I don’t think the concern is about sending nudes to kids or adults who don’t want them. And while nudity isn’t inherently sexual, I have seen lots of images that are sexually suggestive, and even some that are explicit. And if I’ve encountered them while casually browsing the galleries or when being given the addresses of members with favorite walls full of explicit content, then I have no doubt that children have been exposed to not just nudity, but explicit content. So the situation isn’t as simple as “don’t send nudes to kids,” and I think Postcrossing would suffer more from banning kids than banning nude images.