Comment 6 for bug 714356

As i expected it is a feature attached to the update-manager. When you go to update, the update-manager uses gnome-power-manager to see if the machine is using an external power source or a battery. Case in point, you ever get the message to "plug in" the machine or "continue anyway" when checking/installing updates while running on battery power? Usually I would suggest that we mark this as a wishlist item but not in this case as the feature you are experiencing is a "safety net" to prevent a system failure due to a computer running out of battery while in the middle of installing software. Have you thought about removing the power-manager altogether since you dont use it?