[tuddman]

To disable that deceptive snooping in 6.0 (Marshmallow):

Settings -> Location -> Improve Accuracy -> Toggle Wi-Fi scanning.

[matt_wulfeck]

Yes but now every app you open is going to pester you about enabling wifi, including google maps, which will ask you every time you open it.

[lucb1e]

I've never seen that, but then I'm running an ancient version of Cyanogenmod (based on Android 4.4.4) that might not be obnoxious yet in this regard.

[jayess]

Any idea how to do this in 7?

[gcb0]

google surreptitiously moved it to the ellipsis menu.

on android 7 and 7.1:

settings > location > three vertical dots on the top right > scanning.

And on this screen disable wifi and bluetooth scanning.

And, you would think that would disable wifi/bt scanning, right? wrong!

on the previous screen (settings>location), you also have to click on "mode". And then select "Device only". If you select "high accuracy" or "battery saving", it will ignore the wifi off on the ellipsis menu and still use it!

And there is more! ...still on the location screens, scroll down. Past the "recent location requests" and see a section called "Location services". It might very well include a "Qualcomm izat accelerated location". What it does? well, nobody knows! does it enable wifi from sleep mode on the chip? it might. it might not. again, who knows?

[dingo_bat]

Same steps.