Having lived in more places than just the USA, I have to agree that ethics are not the same everywhere. Much of what is considered correct and right, or even how to go about achieving the "right" and "correct" is dependent on culture.
For instance, when I was working in South Korea at a university there, I had my students in the computer lab to begin an English language class. My colleague, Dr. Lee, thought she should be in the computer lab. Instead of pulling me out into the hallway to solve the situation, she came into the classroom, and in front of my students, she began using a very loud voice to tell me that I was not supposed to be there, that she was sure she had told me to take my students to my classroom for that class period. In the western world, that would be considered yelling, and rude in any case. However, in Korea, many who seem to be yelling are simply communicating. People seemed loud and angry all the time, but I was repeatedly told that they were just talking. It tok some getting used to. In addition, Dr. Lee saw nothing in the world wrong with communicating to me in this fashion in front of my class. Professors over there have a decidedly different view of their status and the status of their students. Children and students are expected to be seen and not heard, and never would they be allowed to correct a teacher at any time. They are not considered to by anywhere near an equal status as the adults in the schools.
Another example I can think of also took place in Asia. My friends and I were repeatedly invited to attend certain functions, and everyone always said, "Yes" to these invitations. However, it became clear to me that even if you did not intend to go, "Yes" was the answer you gave. Often I was left waiting for someone who never came and didn't intend to meet me. It is considered better to say "Yes" and avoid conflict than to (in my mind) be honest with a "No, I have other plans." To them, it was rude to tell others "No;" to me, it was rude to say, "Yes" and then not show.
I realize these are mostly social examples, but it seems to me that the same cultural differences in ethics and protocolwould apply to business practices outside of the USA.