IPhone activation using someone else's SIM card?

I recently factory restored my iPhone 4 AT&T and it has no sim card so of course it needs to be activated, and I lost mine months ago, if I get my sister's sim card and put it in, then activate my phone, then put my sisters sim back in her phone will I be activated? Will her phone be affected?

Added (1). Zack, I'm not trying to get service I'm just trying to make it work, like an ipod touch.

No, that won't work. The SIM card is basically the "activation module" if you will. Putting it in your phone will just give you her phone number.

I recently factory restored my iPhone 4 AT&T and it has no sim card so of course it needs to be activated, and I lost mine months ago, if I get my sister's sim card and put it in, then activate my phone, then put my sisters sim back in her phone will I be activated? Will her phone be affected?
------------- yes… ATT will think she has an Iphone 4 now… When you activated it via itunes, the imei # and sim # became paired and sealed in the billing system. Only way to revert back is to upgrade OR call 611, get an agent, and manually update the imei of the old back into her account.

Additional Details
Zack, I'm not trying to get service I'm just trying to make it work, like an ipod touch.
-------------- we understand this… But if you use her sim card, it will activate under her account and her phone number… On GSM technology, the sim is YOU… If you are stuck into something, that device becomes yours. Wel… In this case, your sisters brand new iphoen 4 -- lmao… I would get off your fat american but, simply go to ATT, get a simple sim card for free… Issue resolved… Shoot, call ATT and have it shipped to you.

  • Using someone else's Wi-Fi on iphone, can they still see your app history? Yesterday I went to work with my friend and I used the places' Wi-Fi, I'm at home right now and no longer using their Wi-Fi, can they track my history and app history in my iphone even if I'm not using their Wi-Fi anymore?
  • Using someone else's upgrade? (Verizon)? My mom has Verizon and is eligible for an upgrade. I'm not on her plan nor do i even have verizon. Is it possible to order an iphone (iphone 4s or 5, haven't decided) using her upgrade but transfer that phone to me?
  • Using someone else s old iPhone? I currently have an iPhone 5. My sister has a 6 currently but she had a 5s that isn't used and while I'm due for an upgrade IIm holding off for another month and a half until the next iPhone comes out. Is it possible to just put my SIM card in her old phone and use that or is it more complicated? Like do I have to go to the apple or Verizon store (my cell carrier) to do this or can I just do this on my own?
  • Is using someone else's computer to charge you're iPhone safe? Hi, if i were to use someone else's computer to charge my iPhone and iTunes pops up automatically does it usually back up my information on that computer? Or do i have to do it manually for it to back up and sync.i'm worried my personal stuff has been backed up on someone else's computer.