As many as 30 countries may be suing Google for data collection taken during the Street View project from unsecured (Wifi) hotspots.
The countries investigating Google's actions include the United States, many countries in Europe and in Asia. Google has publicly responded to the investigations, saying that they believe that they have not done anything illegal. In a statement, Google released the following to the House Energy and Commerce Committee: "We believe it does not violate U.S. law to collect payload data from networks that are configured to be openly accessible."
Part of Google's defense will be to say that they did not look at the data they collected. Additionally, they claim that the data collected was unintentional and the code that captured the data was "rogue and mistakenly" programmed.
Google sent their response on June 9, 2010 to the Committee of the United States House of Representatives. The following citations come from that letter directed to:
Question: Over what time period did the collection of information for Google Street View take place or, if roads are visited by Google Street View vehicles more than once, what is the schedule for return visits to roads?
Answer: Google began collecting WiFi data via Street View cars in 2007. At that time, payload data was being collected.
Question: Please explain in detail why Google chose to collect the data and how it intended to use the data.
Answer (partial): Google collected and uses network information broadcast by WiFi routers (such as SSID and MAC address) to improve the accuracy of the location-based services. [ ... ] Because GPS and cell tower location data can be unreliable or inaccurate, in some cases using the location of WiFi access points can enable a smart phone to pinpoint its own location more quickly and accurately.
As part of their defense, Google states that the code that captured the payload data was not intended to be part of the system, and when Google became aware of the situation, they grounded all cars and bikes doing the collection and photography.
Additional sources: https://googleblog.blogspot.com/2010/05/wifi-data-collection-update.html