I got this iPhone 4 used for a good price and my plan is to use it like an iPod with a good camera, and not use the phone. Now I want to stay away from the jailbreaks because then I can't get OS updates until hackers make it safe again, so what happens if I buy a prepaid sim card and don't register it? Will I be able to activate the phone with it? If that doesn't work, what happens if I buy a prepaid sim card that is registered properly, and it activated the iPhone... lets say the card expired like if I used the minutes up on it... will it continue to work as an iPod? I heard if you attempt to update the device with an expired sim card, iTunes will detect this and lock your device and require you to reactivate? Is this true?