Well; given that TiWorker is just the executable behind the Trusted Installer (goes as Windows Modules Installer in the services tab and handles Windows Update tasks) service... My guess is that the reason for it "phoning" home is that it wants to constantly check for "updates", "fixes", etc.
The default for that service on Win7 is Manual (Started)... I stopped it on my daily driver PC and it only runs when I manually launch windows update every week or so... Not sure if you can do the same in Win8, but it would be worth a try.