When the data snooping came to light back in 2010, Street View cars had already been extracting private information from insecure personal Wi-Fi networks approximately three years. According to Google, it all happened under the radar, and as soon as it found out about, it fessed up, apologised and promised to delete all the questionable data. Turns out it didn't.
The news came out when the UK Information Commissioner's Office published a statement saying that:
Google contacted the ICO to confirm that it still had in its possession some of the payload data collected by its Street View vehicles prior to May 2010... Google indicated that they wanted to delete the remaining data and asked for the ICO's instructions on how to proceed. Our response, which has already been issued, makes clear that Google must supply the data to the ICO immediately, so that we can subject it to forensic analysis before deciding on the necessary course of action.
Just like when news of the breach broke, Google has called this a mistake and apologised. It's motto may be "Don't Be Evil" but it's certainly opted to act first and apologise later at every stage in this whole debacle. Maybe it ought to devote a little more attention to "not being oblivious, messing up, and claiming ignorance every step of the way." [AllThingsD]