When stating a full non-Japanese name, should one use the "Surname Firstname" rule used for Japanese names (i.e. "Smith John / スミス ジョン") or the name's native rule (in the case of an English name, "Firstname Surname" (i.e. "John Smith / ジョン スミス")).
Which format would native Japanese speakers use, when stating an obviously non-Japanese full name?
Typically, you state it in the order that is normal for your language. Koreans and Chinese say their family name first, Americans say it last. Japanese people are well aware of that language difference, so they expect us to keep our names in the original order. They also use the original order when saying foreign names themselves.
The only times I put my last name first is when I'm required to do so, as in opening a bank account.
When speaking Latin .... do as the Romans do, is one method, and I use it.
In Japan I always use (surname)(given-name) order when writing in Katakana, or when pronouncing my name in Katakana while speaking Japanese. If talking to a person in English, then I will use English pronunciation and (given-name)(surname) order. If, in Japanese, I am asked to pronounce my name in English, then I will use (given-name)(surname) order to do so. My meishi has English on one side, Japanese katakana on the other, and the different order on each.
It has worked out fine. Occasionally someone newly met person will request confirmation, but I think that would happen no matter which system was chosen due to the inherent ambiguity.
Japanese people overseas seem to use the same system, matching their name order to the language they are speaking.
I don't think there is a general fixed rule, but there may be a rule in your company or school.
