Tried that. That's only enable and disable the flow of data but the cdma radio is still powered on. If you turn your wifi off and uncheck enable data you will the at the bottom right the signal meter of the radio. Makes sense?
Sure, though it accomplishes the desired effect of not using the data connection. You would still use some battery running the radio, but compared to the 10 inch screen and core processing requirements of the device that radio doing heartbeat beacon signals is very little impact.