I wouldnt say that all of Google's public data is "no longer true" only some of it is. The reference (On page 340) refers to Geodata such as images or data on terrain, and map data. That would not be in effect that much for the Government. They have their own technology in place separate from google that they could use to always be up to date if they needed to . The government could just point one of their satellites at whatever they needed updated geodata on and get it that way without any help from Google.
Data no longer being true has always been a problem with Geodata. theres just so much of it that gets updated so quickly that any company would have trouble using it. New buildings and roads are showing up all the time, and it is up to Google to find a way of keeping up with that. Annotations only work to a certain extent. In the end, Google and other mapping services are just a tool. It is up to the end user to determine if the information the tool is giving them is correct or not. There are certain things i trust google for, and certain things i use other mapping services for.. For example. when it comes to hiking Google tends to be mostly reliable for topographic and trail information, but there are times when you have to refer to USGS quadrangle maps instead for reliable information.