It is not common to tip in Japan, so I guess people would do that en lieu and to make some buzz, but a couple of times, at the restaurant that I work at, customers would leave their serviette folded in a crane or something. That was way cooler than those messages.
I have a similar story with language and video games as I vividly remember looking up Japanese words to play FFV, FFVI and Chrono Trigger on my Super Famicom when I was in high school.