Idea #10454: NM should not connect automaticly to unsecured network which was formerly secure

In my opinion this is a security problem. I can think of two scenarios:
* You are able/allowed to connet to a secured network and trust all other participants on that network. Now, by mistake, the encryption is disabled by the AP administrator. You still send confidential data over the network without knowing that everybody can evesdropping.
* Maybe this problem is also usable for an active attack: Is it possible to provide an access point with the same ssid / (MAC?) in a way, that it 'shadows' the proper access point? (sending with more power, sending on a different channel?)

Once a connection was established to a encrypted network, there should at least a warning if that encryption no longer exists (changed?).