hello, since it's cheap to get the iphone 3gs now, i think im going to upgrade my current old none smart phone from at&t. The problem is the data plan, I plan to cancel the data plan after first month of use, because im an cheapo and have wifi at work/home. does jailbreak/unlocking/fake apn can make att think im not using a iphone? so they wont add the data plan back. also does this guide from this link work? http://www.iclarified.com/entry/index.php?enid=657 since imei is the only way att know im using a iphone? or is there other ways I dont know about?