I will state, as one of the archive moderators, I rarely warn an author if the only tag missing is NoSex, just like I don't warn for a missing M/F tag if the story is in the Het subcategory. It honestly shouldn't matter, and I say that as an author as well as a moderator.
Adult fiction means a great deal more than erotica. It can mean dealing with darker themes: loss, anxiety, depression, and the like. There's no requirement that stories here have sex, and there's not even a requirement that stories contain "adult" content. Many authors come here simply because we are an actively moderated archive, and we respond to our members promptly when there is a question or an issue, such as suspected plagiarism. It makes the authors feel safe, because we care about their stories as much as they do.
There are sites that only permit erotic content. We are not one of them, and I for one am quite proud of that.