said by IowaCowboy:
What they could do to stop this is put a hardware based region lock on them so they can only be activated on a carrier in the country in which they were originally sold (even if unlocked) like the region locks on DVDs and Blu-ray Discs.
A little engineering on the part of Apple would put a stop on the illegal export of iPhones. It would have to be a hardware based solution so it would be impossible for hackers to remove the region lock. My proposal does not stop them from roaming in another country (provided they have a sim from the home country where the phone was sold) but prevents them from being activated on a carrier outside the country where the phone was originally sold.
Another solution would be a cheaper version of the iPhone that operates on US frequencies only (GSM 850/1900 and CDMA 800/1900) instead of international (GSM 900/1800).
Hmm, bad idea, I have a unlocked phone that I purchased from the carrier, I travel throughout the world and get sims for the various carriers in the countries I travel in to avoid huge international roaming charges, what you are trying to propose would make the ability impossible.
Also manufacturer already have different phones based on different frequencies, but a lot of them overlap so that would be impossible to do - and it would not be cheaper, it would make it more expensive due to the increase in manufacturing costs and the fact the number of devices sold before a profit is returned would be a lot higher