Pixee is not an adult app. Posting adult content is only one of the possible use-cases (obviously this thread focuses on that), other might be: selling photos to news sites, trading college assignments etc.
From our user research, we already know people are using it for that.
So, I'm not a lawyer, but wouldn't you need a content policy stating that there's no nudity, ect. in order to stay compliant with the terms of the various app stores? I know Android/Google would at least ban this app if they saw how it was being leveraged this way, and that it was being encouraged to leverage it in this way.
From what I understand, nobody really cares about adult apps on phones, but they're fairly ban-happy when it comes to their app stores.