[bmacho]

AFAIK USA people learn both systems in school. So it understandable if they are not aware that the rest of the world don't know about their system, miles, inches, feet, gallons, pounds, etc, unless they are into American culture (books, movies).

[pxc]

One of the things that USians are taught in school when they learn these two systems is that everyone else uses metric. We're typically taught it in our science classes, because even in the US, scientists still use predominantly (exclusively?) metric. It follows that there's no parallel reason for most foreigners to learn US imperial units, especially in an institutional setting like public school.