Japanese send more SMS messages than anyone, and often from crowded trains where it is hard to get any kind of privacy. People just want to know their conversations are private, but is that really something you worry about? This illustrates one of the hardest things to adjust to moving to japan. japanese are purposefully vague and discrete about their personal feelings. They go to extremes to keep private things private. especially girls. especially on the crowded trains with the groping hands and learing eyes of lecherous salarymen.”]
Source: https://gizmodo.com/hello-kitty-privacy-sticker-hides-your-phones-texts-em-285098