I'm buying an AT&T iPhone 4 tomorrow from a person on Craigslist. I just have a couple questions to make sure I don't get, um, hustled. As someone who is on Verizon and not due to upgrade for another 8 months, I have no experience in either iPhones or GSM phones. The phone is a gift for my girlfriend, so I can't bring her along to test it out or anything. I know that with Verizon if a phone is reported lost/stolen, they blacklist the ESN and it can't be activated. I know AT&T uses sim cards, but is there anything similar that would keep the phone from being activated once a card is popped in? Since I don't have AT&T, I can't just put in my own card to see if it works, that's why I want to be sure. Also, if the phone powers on, am I free to assume that as long as the buttons and sound and everything is functional, then it's good to go? Occasionally I see broken iPhones being sold that say they won't sync to iTunes or something else that I would assume could be fixed with a hard reset (assuming iPhones have them?). I may or may not be getting a sync cable with the phone, so I won't really have a way to test this out. Basically, is there anything I really need to watch out for beyond making sure the phone itself is functional? Sorry for the highly novice level of these questions. I know I could just Google for the answers, but I always see conflicting bits of data. Since I'm getting the phone tomorrow, I felt it would be more useful to get advice directly from people who are familiar with the the iPhone and able to help me out.