Picky picky
Like the rule about cutting your nails short, there is another unwritten guideline that people occasionally forget: “Don’t clean the dust and lint between your toes in a public place.” This young person is obviously acting in such a manner, and a flight attendant actually took a photo of it.
Things do happen when traveling by plane. There is no policy prohibiting him from doing this, so perhaps he assumed that others would just ignore him.
