My girlfriend's phone broke and she's on Tmobile with only a voice plan, no data plan. I want to give her my old unlocked iPhone 2G. My main concern is that the iPhone will make certain data transfers unexpectedly (checking mail, accidentally opening some app like Stocks, etc.) If she has no data plan, will such transfers take place, or will she receive an error when trying to use EDGE? She just needs to be able to make calls, text, and use wifi. Thanks for any help!