In theory, if that becomes a big enough hole, the market should rectify it on its own. You can already go to Starbucks and buy $10/lb 'Fair Trade' coffee, and

In theory, if that becomes a big enough hole, the market should rectify it on its own. You can already go to Starbucks and buy $10/lb 'Fair Trade' coffee, and many 'hip' brands (American Apparel comes to mind) trade on their humane wages and treatment of workers. I'm not saying it's a complete solution (some of the costs are still likely being externalized, although that's more a problem in the case of pollution than labor), but in general when a savings is made because of a negative externality (it's 'costing' others, instead of the just the buyers), a 'non-negative' version will spring up, and sell for a handy markup.