Something that might not have been considered, is that in a manufacturing environment in some cases we are forced to continue using older operating systems like Windows XP. Reason being is because that is the only operating system meeting the tool software system requirements... and the manufacturer is out of business or no longer supports that tool line so we are stuck with it. Last week, it was necessary to perform a Windows XP service pack 3 install on a tool computer. The install went well initially but when it reached near the end with a message "Performing cleanup" it did not finish. I've read that actually the program is trying to install updates in the background when it displays performing cleanup. Now that the service pack cannot check for updates, I believe that it will hang indefinitely for everyone... wasting their time as they are diligently waiting for the install to properly finish. After an hour of waiting I finally just rebooted the PC and luckily the service pack installation appeared to have successfully completed.
Maybe Windows XP SP3 is the only case, but I think Microsoft should modify the highest level service packs for each pre-Windows 7 OS to not check for updates during service pack install if updates are no longer available.