A popular meme says the teachers in Japan don't have to bow in front of the Emperor and that's because without teachers there would be no emperor.
Since my understanding of the whole bowing system in Japan is that it's not something required by law, but it's just a way to show respect; no one in Japan HAS to bow in front of anyone. So I interpret it to mean "If a teacher does not bow in front of the Emperor, it is not being rude; it's a custom."
Is this a real custom?
It's in Italian but the meaning is the one I specified already.