It is because the iPhone 4s is a world phone! Sprint/Verizon world phones always come with a SIM card, so that roaming works properly and is billed to your account... You can still unlock it and use it across seas with a prepaid SIM from any place you are visiting and pay that way to save money.
answered Dec 10 '11 at 17:06
The iPhone 4s is one model used by all carriers, that runs both CDMA & GSM. The iPhone 4 had separate models, GSM & CDMA. The iPhones prior were strictly GSM.
answered Nov 28 '11 at 01:25