I think most everything you ask is answered in the thread you referenced. One, don't worry about it. Today, on most flights you are advised when you can turn on your electronics. Most flight crew know a BlackBerry can used with the radio off, and see them hundreds of times each day.
Turn off the radio (manage connections) before you power down the device when the aircraft shuts its doors. Then, when you turn it back on in the air, the radio/data will be off.
Throwing caution to the wind and breaking FAA rules and aircraft policies would be stupid nowadays, considering an Air Marshall would likely be escorting you off the aircraft if you do so blatantly and in their face after being asked not to.