I'm buying an Air w/ cellular service for my non-tech mom. I know she will enjoy cellular service while traveling but she only does so in warm months. The other months I doubt the iPad will leave her house. I've read that VZW will deactivate the SIM if not used for 5 straight months & getting a replacement pre-paid SIM is tougher that a steak cooked for 30 minutes. A) is this true B) is this standard practice or is ATT, Sprint & TMob more lenient?