Lol.. I probably AM that guy
To answer your questions:
1). I do not have to do anything to unfreeze.. It just starts working again in 4 or 5 secs.
2). Reassigning controllers doesn't make a difference.
3). Issue does nto happen if i use USB cable.
4). Sometimes, the the controller actually goes offline and prompts me to connect the controller. In which case i have to hit the PS button and it starts working. But that is rare.
All in all, i think the issue is with the Bluetooth communication between the controller and the PS3.
My bluetooth headset works fine. during the time the controller craps up. So i know its not the blue tooth controller on the PS3.
I am really stumped.. not sure what is going bonkers with this thing.