(posted with mobile device)
Consider the following questions.
Was Google using the wifi protocols to request information from others or were they listening to existing traffic?
If others voluntarily respond to Google's requests, that should not be an issue. This is the way that wifi is supposed to work.
Wifi devices need to listen to transmissions from other devices to determine if either data or a request is being sent to them. These are sent over public air waves. What may be unusual, is that Google may have been saving them, but Google has a reputation for saving data.
Once Google gets such information, should they be allowed to put it in a database or analyze it? Should they be allowed to use derived information to improve their mapping and other services? Should they be allowed to publish it or sell it? Should they be allowed to give the NSA or other government agencies access to either the raw or digested data? Do various governments already do similar themselves? Is Google assisting governments in circumventing legal restrictions?
Should Google be entitled to copyright this information? Was it in the public domain when Google got it? Does it consist of facts?
Was Google transmitting too many requests and hogging or overwhelming any wifi resources?