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The combination of occasional GPS/Wifi location data and continuous IP data is pretty powerful though.

There's a setting hidden away in android allowing apps to scan local wifi/bluetooth networks even when wifi is turned "off". Enabled by default of course.

What settings is that?

Security & Location -> Privacy -> Location -> Scanning

(Supposedly; I don't own an up-to-date Android device.)

Settings > Location > Improve Accuracy

2 settings, one for Wi-Fi scanning and one for Bluetooth

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