|Possible counter measures?
A recent reader e-mail asked for help with a Chinese CD player that had gone bad. The US importer couldn't assist since it was a discontinued 240V grey-market unit for which he'd never received schematics or parts. Three owner e-mails to the Chinese factory had gone unanswered. The customer who bought from eBay now owns a non-functional machine whose promotional materials assure a 5-year warranty.
It's apparent from the widespread evidence that manufacturers cannot control official retailers from moving product out the back door and into a different country. They may be able to track such activities after the fact if and when a service call attached to a serial number is received - but if the product doesn't break down, such tracking won't ever activate.
However, not answering customer e-mails doesn't make the problem go away. Plus, it's simply an inexcusable business practice. The very least one expects is that the manufacturer list unauthorized grey-market resellers - those he can't shut down since they're secretly supplied by official retailers in the home country. Such a listing should be on the opening page of the website to warn customers that any product purchased from such vendors carries no warranty and service request e-mails will be ignored.
6moons is happy to review products from Far-East Asia. Yet reports from the field that pose evidence of irresponsible lack of customer service will of course prevent us from considering such brands (though, again, we mostly hear about such issues after the fact, too). Grey-market sales are a reality of international web commerce. Consumers engaging in them knowingly take -- hopefully calculated -- risks and are on their own. However, there will be the occasional instance of honest innocence where a transaction was conducted through an apparently legitimate outlet, i.e. the buyer was unaware of any subterfuge. It's such incidents that could be minimized or altogether avoided if the manufacturers published an open disclaimer on their websites. For example: "Any ABX product purchased in the United States second-hand or from anyone other than Audio Excellence or their authorized agents carries no warranty. Audio Excellence or ABX will not respond to any service calls for products purchased not directly from them. To assure ongoing warranty support, contact us with the serial # of the unit in question before purchasing."
Preferably, there'd also be a list of the three or four most defiant international grey market audio pimps, clearly marking them as unauthorized pariahs to be shunned at all cost. Lastly, any manufacturer truly concerned about long-term viability and reputation merely needs to buy back a single unit from any specific unauthorized reseller to track to which authorized store the unit had originally been sold, to subsequently be expedited offshore. Otherwise, proudly issuing 5-year warranties without open disclaimers or specific conditions attached becomes dishonest and leaves customers open to abuse. Plus, not answering customer e-mails with service requests is simply outrageous, period (and in this case, the customer is fully prepared to pay for the repairs - he simply wants to get the unit working again)...