Yes, likely. It'S plausible that Google captured Wifi signals in order to get to the SSID etc. to build a location database and they forgot to cut of the data part, possibly assuming it was encrypted anyways. Considering that they announced the mistake themselves and the short time the car was in receiving distance makes this a quit believable thing.

Similar here: The developers logged information onto the device itself in one version of the software and didn't hesitate to push a new release.

From an engineering perspective relatively small bugs. Impact a bit larger.