So the can story is just a story about the cultural difference in usage of different languages. For some, it is an offensive story, for others, just a small talk.

I asked my girlfriend about the 4 seasons. She said she learned a lot about the world from her well educated and internationally minded mother, so I can't at all say what is taught in school.
I cannot say anything about her mother. I sometimes notice something like "younger generation is different in Japan", but her mother is a great example, older generation is also different here.

If she had not been educated in Ireland or wherever outside Japan for all her school life, it is easier for her to tell you a bit about what she did in school, I suppose. I don't deny she met some stupid students believing in "4 season in Japan" in the past, but this is also the same in other countries except Belgium as in the provocative John Stossel's program, 'Stupid in America'. No Stossel here, but I often watch "Learn from the great Indian/Finnish or wherever education" here.