So here's the deal. I'm on a family share plan and I got my iphone 3gs in August of last year. That means I can upgrade to an iphone 4 for 200$ next year in august I think or for 400$ now. The plot thickens: my sister has a 3gs as well, and is eligible for a full on upgrade. She couldn't care less about an iphone 4 or her contract length. If she gets the upgrade priced iphone 4 for 200$, will she be able to somehow use her old iphone 3gs and give me the iphone 4, which I could then activate or hacktivate using either my current sim which I would have to cut, or a new micro sim? The real question here is how to get my sister back on her iphone 3gs after she goes into the store and upgrades to the 4. Could I do this by buying the 4 off the apple website, and then just never having her activate it? Just jailbreak +hacktivate it on my end? I read somewhere that microsims are tied to their hardware using ICCID to prevent people from using ipad sims in their phones, so I dont think (?) I could use one of those little micro-sim adapters.