Comment 8 for bug 387382

I've now written the relevant parts of the specification <https://wiki.ubuntu.com/SoftwareUpdateHandling>:
a. "Update Manager should launch automatically, in the background but not minimized, when the computer has been connected to the Internet for at least one minute, you are logged in as an administrator, and either..."
b. "Whenever the computer is not connected to the Internet, the [Install] button should be insensitive and have the tooltip “Not available because there is no Internet connection.”.

If anyone would like to implement both of those, I think that would be enough to fix this bug. There are a couple of other details I need to cover (what should happen if you get disconnected during updates, and what should happen if for example a wi-fi hotspot feeds you HTML login pages instead of software updates), but those can wait till later.