Location access started being required for WiFi scans in Android 6.0 Marshmallow (2015). https://developer.android.com/about/versions/marshmallow/android-6.0-c

Location access started being required for WiFi scans in Android 6.0 Marshmallow (2015). https://developer.android.com/about/versions/marshmallow/android-6.0-changes.html#behavior-hardware-id https://developer.android.com/about/versions/marshmallow/and... By eye, that covers nearly 75% of current devices.