When I last left off, I was waiting to hear back from my AT&T representative in the office of the president, to see what she learned from the internal information request that she put out. Well, she called me this afternoon, and I finally have some more definitive information, even if I don't like it.
AT&T's official policy on iPhone unlocking is that when I signed the contract with AT&T at the time that I established service on my iPhone, I agreed to only use my shiny new iPhone with AT&T. My AT&T representative confirmed that the unlock code is provided by the manufacturer, but it is up to AT&T's sole discretion to provide the code to their customers. She said that because the iPhone is a device that is only designed to work with AT&T (which is of course patently untrue), AT&T will not supply the unlock code to its customers.
I did some digging into the Service Agreement, and while it's a little generic, I think that this is the passage that she was referring to:
"DEVICE
Your Device must be compatible with, and not interfere with, our service and must comply with all applicable laws, rules, and regulations. We may periodically program your Device remotely with system settings for roaming service, to direct your device to use network services most appropriate for your typical usage, and other features that cannot be changed manually. Devices purchased for use on AT&T's system are designed for use exclusively on AT&T's system ('Equipment'). You agree that you will not make any modifications to the Equipment or programming to enable the Equipment to operate on any other system. AT&T may, at its sole and absolute discretion, modify the programming to enable the operation of the Device on other systems. You can get details on AT&T policies for modifying Equipment by calling 1-866-246-4852."
It's interesting that while AT&T claims that it's a violation of the contract to unlock your phone (which presumably covers jailbreaking as well), I've yet to see any press about AT&T actively enforcing this policy by kicking customers off of their network.
Nevertheless, this seems fairly ironclad. And while it's still somewhat of a mystery as to why the iPhone is the only phone for which AT&T will not supply an unlock code, I'm not sure what my next step is. Since I find this policy to be distasteful, I would love to take my business somewhere else -- but my guess is that all of the major cell phone providers in the U.S. have similar terms of service.
-Andy.