I lived in Japan for nearly 6 years and found that concern for faux pas such as these for hashi (chopsticks) are way way overblown. I used at least one thousand disposable pairs of chopsticks in Japan and never had the desire to smooth them -- they are higher quality than Panda Express offerings. I knew about this "taboo" prior to arrival and it was simply irrelevant. Avoid the obvious symbolic references to makura gohan (bowl of rice offering to the deceased) at the end of your meal and you are probably golden. If you have kids in Japan, gaijin passing food with chopsticks to their children in a restaurant is going to be seen in a neutral or even sympathetic light. The Japanese may silently judge but they rarely sneer or harass. If you spend a lot of time with modern Japanese families you might be surprised to discover Western stereotypes of Japanese taboos are sometimes outdated and even incorrect. They are very aware that foreigners will not understand all of their customs, and many of those customs have decreasing importance as their culture evolves.