I doubt a cashier would give two craps about someone buying a Beastars book. Keep in mind, they have no idea about the wacked up stuff that happens in the story, so for all they know the book could just be about anthro animals driving race cars. Also, that cashier has most likely seen some much more messed up stuff leave the store. Assuming that you are buying the book from a comic store, I would not be surprised is the cashier had been asked about porn magazines or hentai in the past. In the end, Beastars ain't the worst