Originally Posted by dbenampaka
Actually there was no question; Therbo made a statement. Anyways, AT&T does not "unlock" the iPhones; Apple does. AT&T forwards the IMEIs to Apple, Apple updates their data base, and when you restore though iTunes, the unlock code (command) is then transmitted to your phone. You recall that iTunes can re-lock jailbroken and unofficially unlocked iPhones, right? Same philosophy.
uhhh, yeah. And whether a restore through iTunes is required to complete the unlock or not has nothing to do with your subsequent comment "In the US companies like AT&T subsidize many iPhones; hence they want them locked to THEIR service."
So again, given that with other carriers, when they perform the identical unlock through Apple's mechanism, why does AT&T's instructions require an iTunes restore? I have had multiple iPhones unlocked through my carrier and I only used iTunes to restore the first. The second one I simply inserted a SIM from another carrier and presto, it accepted it. Worked for the next two as well.