I noticed that many Japanese businessmen tend to address the colleagues they are traveling with, or even introduce themselves as ◯◯◯さん. This would clearly be a faux-pas in a Japanese-only meeting, yet ...
When addressing John Doe, would you say "John-さん", or "Doe-さん"? Does it depend on how polite or formal you're being? Does it also depend on whether the person is a nihonjin, a kankokujin (who have ...