When Google introduced Jelly Bean 4.3, they said there is an option to let Google's location service to always scan for WiFi networks even when WiFi is off. To stop always scanning WiFi Networks on Jelly Bean 4.3 do as follows:
1. Open Settings and then go to Wi-Fi.
2. Press Menu button (or tap the three dot icon) and then select Advanced.
3. Make sure to uncheck the Scanning Always Available option to stop this feature