About a year ago i was having breakfast with my sister & i put her sim card in my iphone 3g to see if it would work(we are on att family plan) It did work but she soon got a message from att telling her she had to buy a data plan as she now was using a smartphone.we told them it was a mistake & we were just trying it out.Now months later I have unlocked my iphone & my question is....if i put her sim card in again would att be able to tell her sim cardf is in a iphone & try to charge the data plan again or since my phone is now unlocked would it just show up as i regular phone???