Description of problem:
It looks like NM can choose the wrong credentials to use when connecting to a wireless network in some cases.

In my network I have an access point which has been configured as unsecured. NM learns the SSID and the fact that it can connect without a password. Then the access point was reconfigured and a password was required. After this point NM maintains two entries in its list of known networks. On booting the first one (unsecured) is chosen for the SSID, which is unchanged. This fails to connect and NM doesn't know to try another one.

To its credit, NM presents a list of two entries for the SSID, however they look the same. Also, it seems it's not possible to edit the list or delete an entry (I will raise this as a separate BZ)

Version-Release number of selected component (if applicable):
NetworkManager-0.8.998-2.git20110406.fc15.i686

How reproducible:
100%

Steps to Reproduce:
1. configure AP as unsecured and connect with NM.
2. reconfigure AP with WPA PSK and connect with NM.
3. reboot and try to connect with NM
  
Actual results:
Network connection is no longer made automatically. Furthermore there may be potential for DOS or worse if NM is allowed to choose or learn an unsecured similar SSID to an existing one that is secured.

Expected results:

Ideally NM would warn before allowing users to choose an unsecured network that looks like a previously known secured one, as this may be an attack.

I would suggest that a sane network environment would not mix secured and unsecured networks with the same SSID / lower layer address details, therefore there should be only one setting remembered for each of these.

Additional info: