You’d have to demonstrate that all other countries not only just use metric, but also only sell products that already only have metric on the packaging. I don’t doubt dual labeling is heavily a US thing, but I doubt it’s only US. Simply to keep packaging making universal. Now that could be altered if such a ban was put in place, and maybe most non-US places wouldn’t care too much…but we need a sampling of what’s already out there to even say if it’s a thing that can be used.