I'm not sure I follow. Why would a network known to the device not be connected to the network? If you never connected your device to their wifi and only connected to your wifi connected via ethernet, why would it even know to make a request? If you're not actively connecting to the WiFi in your house, why not just "forget network"? Seems like a strange hypothetical, but aren't they all?

They do that already... sum of all privacy losses.

Any time you go out in public your devices are crying out looking for your home AP. If someone can figure out which are you, e.g. by seeing you multiple times in different places they can then go look up where you live based on your home's SSID broadcasts.