Yes, non-Vienna-influenced countries are technically in the minority, but not such a minority that laypeople necessarily even know they’re in the minority. (In case anyone is wondering, 46% of the global population live in the countries that aren’t parties to the Vienna Convention, and several signatories never ratified it.)
Even among Vienna Convention countries, either some signs are inconsistently implemented, or local communities have been ascribing extra meaning to the signs that doesn’t generalize across borders. At least that’s the impression I get from the half the discussions about highway=path, where some have said, “We don’t have this sign in my country,” or some have debated whether the same exact blue disc can refer to two subtly different situations. That’s why it’s important for any sign-to-tag recommendation to indicate a jurisdiction where possible.