I presently have an iPhone 4. If there are three upgrades on my family's plan, would Apple let me use one of the other upgrades that isn't my line? I know AT&T will so long as I have the last four of the social of the main account holder, but will Apple? I do not live in the same city as my family anymore, so it would be a bit of a hassle to have them there in person in order to do so. I will probably end up going to an AT&T store, but this is mostly in case they are out of stock. Not sure how much stock the AT&T stores here in Orlando have of the white 16GB models.