That would make a lot of sense, but regardless, Artemis felt certain that there had never been any of their kind at the Gala before. Surely, in spite of Don't-Ask-Don't-Tell, which only applied to soldiers anyways, and given that the batponies had only been in Equestria for two years now, word would have gotten out if any of them had attended a previous gala. Especially if they didn't even try to hide their bat wings!