Hmm, I haven't heard about sunglasses and poop, but I have heard about whistling at night. I was whistling in my house at night and my mom cut me short, saying, "Don't whistle at night because a burglar might come and rob you." At this point I picked up a lighter and started flicking it on and off. Again, my mom chimed in, saying, "Don't play with fire or you will pee in your bed tonight." Seems Japan has a lot of superstitions, but then again so does America (black cats, walking under ladders, shattering mirrors, etc.). I can't help but think the latter saying was just to scare little children into behaving, much like the boogey-man.