Only in a recent firmware (2.3x or 2.4x) update did they even make it so that you could do an update without the controller plugged in. And these controllers DO have to be connected with the cable at least once for the system to recognize it as a local device, which is a little different than other devices that have to be added via the BT menu. I know this because I bought a used controller from someone and it would not connect to my system until it was plugged in, as well as my son's friend brought one of his over to play COD4 and we had to do the same. While there may not be much going on between the system and the controller, it isn't simply for charging, and you can charge the controllers other ways without the PS3.