Doh! Just noticed you already are aware of that particular work. Anyway, congrats, you're already aware of the state of the art!
Bait and switch would be just like these guys!
Google wants an auto updater so badly because it allows them to gather more information on you. Why else would it have ever included a unique identifier?
The purpose of the ID is described here. But you may need to take off the tin foil hat before you can understand it.
GoogleUpdate also uses its own, randomly-generated unique ID number to accurately count total users. This information includes version numbers, languages, operating system, and other install or update-related details, such as whether or not the applications have been run. This information is not associated with you or your Google Account.