How to disable and remove Wifi Sense? (Sending your Wifi passwords to Microsoft)
In addition to _optout, there are two ways to prevent WiFi Sense from working,
which might not be possible in your case, where I understand you do not control
the environment :
One must sign in with Microsoft Account to use WiFi Sense, so using a local account in effect disables it totally, as well as most other information sharing with Microsoft.
WiFi Sense will not share log-in information for networks with 802.1X authentication, but the infrastructure for using 802.1X is not easy to construct.
Working in IT I looked into this same issue, but the 2 things that people have found and what Microsoft has said is the setting you found in the Wifi Settings and the Wifi SSID.
Maybe in the future someone will find a registry key, but in the Wifi settings you turn off everything in the Wifi Sense menu. The second thing is to change your Wifi SSID to have _optout or the Wifi SSID and password can still be send to Microsoft's servers.
A note to help, at the very least Microsoft has said once it's on their servers, the information is encrypted before sending to any device, and those devices will not have full access to the network using that feature. The problem I can see is that people can probably find a way to gain full access to a network, and just because a password is encrypted doesn't mean it's safe.
The only other option is to not use Wifi, but that's too much trouble and in some cases impossible.
Edit: here's some information from Microsoft just to point out the same information you have.
http://windows.microsoft.com/en-us/windows-10/wi-fi-sense-faq
I'm sharing a network and want to stop it. How do I do that? If you're sharing Wi‑Fi network access and want to stop sharing a certain network, do the following:
To stop sharing access to a Wi‑Fi network
Go to Start Start icon > Settings > Network & Internet > Wi‑Fi > Manage Wi‑Fi settings. Under Manage known networks, select the network that you want to stop sharing access to, and then select Stop sharing.
It can take a few days for the network to stop being shared. This is also true if a user is already connected to the network.
If you want to stop sharing all Wi‑Fi networks that you're currently sharing, go to Start Start icon > Settings > Network & Internet > Wi‑Fi > Manage Wi‑Fi settings, and then turn off Connect to networks shared by my contacts under Wi‑Fi Sense. It can take a few days for the networks to which you've shared access to stop being shared. When you turn this setting off, you won't get connected to Wi‑Fi networks that your contacts have shared with you.
Here's for the Wifi _optout i mentioned:
How do I opt my Wi‑Fi network out of Wi‑Fi Sense?
If you don't want Wi‑Fi Sense to connect people to your open Wi‑Fi network or allow people to share access to your password-protected network, you can opt your network out of it by including _optout somewhere in the Wi‑Fi network name (also called the SSID). For example, mynetwork_optout or my_optout_network. When it comes to sharing, you might choose to do this if you have a Wi‑Fi network at home or at a small business where other people know the Wi‑Fi network password, but you don’t want to allow your network to be shared.
To change your network name and opt out of Wi‑Fi Sense
Use an Ethernet cable to connect your computer to your router or other Wi‑Fi access point.
Open your web browser, and then enter the address of the configuration webpage for your Wi‑Fi router or other access point. The address is usually either http://192.168.0.1 or http://192.168.1.1.
If it's not one of these addresses, you can try a few other things. First, check the bottom of your router or access point, and see if there's a sticker with the address listed on it. If there isn't, you can find the address by typing ipconfig in a command prompt window if you're using Windows (or ifconfig in the command prompt on Mac OS or Linux), and then looking at the address for the Default gateway.
If prompted, enter the administrator user name and password for your router or access point.
If you don't know either one, check the documentation for your router or access point to find the defaults that are used.
On the router configuration webpage, find a text box that's labeled Name, SSID, or something similar, and then type a new network name that has the phrase _optout in it.
Save your changes if prompted, log out, and then unplug the Ethernet cable that's connecting your computer to your router.
To get connected to your Wi‑Fi network again when you're done, choose the new network name, and then enter your network password when prompted.