Now that I have the new iPhone, I want to give my 3G to my daughter. She has a cell phone with a newer SIM card. I don't want to pay for a data plan for her since she will mostly be using it around the house and we have wifi. It's not under contract either. AT&T told me that their system will automatically detect her SIM in the iPhone and will tack on a data plan charge. Basically to use an iPhone you have to pay for data, regardless of the contract status. This doesn't make sense. Can't I just turn off the cellular data and avoid the cost of the data plan?