9to5Google managed to dig into the latest version of the Google TV Setup app and found references to Google using your list of connected subscriptions to automatically install the apps as well as sign into them for you.
Google TV Wants You to Not Worry About Signing into All Your Streaming Apps Individually
This is what the excerpt says, To put it simply, it looks like Google might be pulling the information from a connected device such as your phone. This will allow for a much more streamlined setup process on Google TV devices, potentially letting the users gain access to all the streaming services without going through the process of downloading the apps on their own. Needless to say, Google TV getting this feature would certainly make things easier for everyone and it is something that more devices should get in the future.