Could I put my Verizon Saga SIM in an ATT GSM prepay phone? I've heard ATT users swap their SIM from their fancy expensive smart phones into a crap phone when they do something like rafting or skiing so that they don't destroy or lose their good phone. I'd love to do this for when I'm kayaking. (I never trust a dry bag to be dry). Can I switch the GSM SIM from my Saga out into an ATT phone? I'd assume I have to pay money to them at some point... or would this create two valid destinations for my phone number and cause the national phone grid to collapse?