And complete anonymity. Most people don't care about this, but some of us do, sometimes. You buy a pay as you go sim card for £10, pay with cash, and toss it a week or month later.
Retailers are supposed to take your name and address when buying a PAYG phone/SIM with cash. I've seen a Carphone Warehouse refuse a sale because of it - although they also don't verify the information you give them, so you could just lie.
You have to replace the handset too; calls are likable both to sim and equipment. Buying a prepaid handset with CDMA account esn built in is just as anonymous.
