So has no one else tried this?
My sister is spending the summer in Europe, so I recently requested an unlock code from AT&T a couple of weeks ago for her phone. A day later I received an email saying that my request was approved and it gave me instructions how to use the code, but it didn't actually send the code. After calling and getting the code from a representative, I had my sister try it out. From what I've heard it should have ask for an unlock code as soon as she turned the phone on with the new SIM, but it only asked for a SIM PIN and no unlock code (and after entering the SIM PIN the phone carried on as usual, except that it couldn't find a network signal (although it could find the network when she went to Settings > Cellular).
Any ideas, anyone?