At least America or England, if people saw bad English they have a tendency to want to tell the owner if it is wrong. What would happen if Japanese person saw bad Japanese. They obviously don't give a damn if blatantly bad English is shown in the public and they don't think the shop is run by fools so I wouldn't shop there. I see scribbled kanji on signs and apparently it doesn't worry them. But what something worse like the wrong kanji or even the wrong word, what would they do? If possible provide an example.