Comment 7 for bug 549140

After having reported this to the NetworkManager developers in https://bugzilla.gnome.org/show_bug.cgi?id=620218, it turns out the issue might rather be related to the driver itself than to NetworkManager. This makes even more sense when considering that recently I ran across a disconnect when doing manual scans with iwlist for testing purposes - worked three or four times, then immediately after another scan the connection was lost and the device locked afterwards. This needs further testing (manual connection using wpa_supplicant without NetworkManager, and periodic scans with a shell script), but I am rather sure this is a driver / hardware issue.