I talked to a friend of mine who worked at an official at&t store. He said that every at&t account is monitored by at&t watchdog called snooper. He got an iphone 3g and from his experience one time, the moment he put a simcard from his blackberry into the iphone and turned it on, snooper detected it within 15 minutes.
every iphone is supposed to have a data plan. so if you don't have a data plan, and you were unlucky enough to have snooper catch on to you, snooper will automatically send you a text warning about possible data interruption etc. then snooper will flag your account. any future data usage not covered by a proper data plan will be charge to your account. if you ever get excess charges, you can go to an official at&t store and get it credited BUT if the reps pull up your account and see that you've flagged and warned, your request will be denied.
if you don't have the right iphone plan but haven't received a text warning you about it, there's a good chance snooper haven't noticed it and consider yourself lucky.
every iphone is supposed to have a data plan. so if you don't have a data plan, and you were unlucky enough to have snooper catch on to you, snooper will automatically send you a text warning about possible data interruption etc. then snooper will flag your account. any future data usage not covered by a proper data plan will be charge to your account. if you ever get excess charges, you can go to an official at&t store and get it credited BUT if the reps pull up your account and see that you've flagged and warned, your request will be denied.
if you don't have the right iphone plan but haven't received a text warning you about it, there's a good chance snooper haven't noticed it and consider yourself lucky.