[eesmith]

"merely to prevent poor people from wearing clothes that resembled the clothes rich people wore"

Or Tyrian purple. Quoting Wikipedia: The production of Tyrian purple was tightly controlled in Byzantium and was subsidized by the imperial court, which restricted its use for the colouring of imperial silks.[7] Later (9th century)[8] a child born to a reigning emperor was said to be porphyrogenitos, "born in the purple".

How would the government convince people that a purple car is a sign of luxury, and thus worth paying the sumptuary tax?

The "Made in Italy" mark (see https://en.wikipedia.org/wiki/Made_in_Italy ) is more strict than the EU laws, which allow shoes which are only finished in France/Italy to be "made in" those countries.

If people were interested in real authenticity, as this article suggests, then why aren't they looking for such marks already? Or are they?