Here's my plan: Upgrade to a new iPhone 3GS and initially add data for one month. I will actually pay for the data for one month and the upgrade fee of $18.00. However, before the month is up, I will use AT&T's POS to change my hardware IMEI, remove the data plan, and not use my phone at all. I will switch out my sim card and stick it into another phone completely. The point of this would be to have an iPhone laying around not being used for phone service but get it for the upgrade cost. Is this possible? Or will AT&T figure out the IMEI was changed and slap the data plan back on?