I was told by customer support that swapping sims from phone to phone will eventually "fry" the card. I think she meant deactivate, not fry, but either way this is inconsistent with many on this forum who imply swapping a same size card is mechanical only with no consequence. Of course, Iwould never do it with the phone powered on, nor could I, since the battery in my phone must be removed to get to the card(not an Iphone). Customer service also told me that, since the sim issued with an ATT purchased phone is matched to the phone imei id#, this mismatch will eventually be seen as a stolen card or phone and deactivate the card, which then can't be reactivated but must be replaced. The imei # mismatch does make sense, but I have never heard anyone discuss the fact that swapping sims routinely creates an imei mismatch. I did a swap and it worked, but then I swapped it back because of what I was told. Am I being misled by customer service? I also noticed that my account picture identifier of the phone linked to my number changed when I changed the card, as if the card phone number is not the only identifier of the phone, but perhaps the imei # is used for that. This brings up a second question. If I have a basic phone account, and place my sim in an older smart phone, which I tried abnd it worked, will the network then catch this and deactivate, even though I dont exceed call, text, or data usage?