I don't necessarily believe that the sim card will play a role in this problem but the symptoms i'm talking about could be and i think are due to poor handling of the cell on the phone side. As several people have mentioned, this isn't a problem observed with other phones in the same place and network, so your sweeping statement that this not being a bug is not constructive in the overall context of the thread. I realize you are talking specifically about the sim card but that's not the main idea here.