Allowing grey goods breaks down monopolies and passes on lower prices to consumers.  Allowing grey imports means that manufacturers do not concentrate economic power in a monopolistic way which can be damaging to free trade (even Adam Smith1believed certain monopolies were antithetical to free trade). Banning them is tantamount to granting a licensed monopoly or cartel on a country-by-country basis, which inevitably means higher prices for consumers. As manufacturing has increasingly been relocated into a smaller number of offshore countries, rather than in the country of purchase, it makes sense that other parts of the supply chain should make a similar move so that they too can realise the efficiency benefits of a globalised economy.  1 Smith, Adam, "An Inquiry into the Nature and Causes of the Wealth of Nations" 1776