Comment 118 for bug 291760

This blog post suggests that the problem has been addressed somewhat upstream:
http://blogs.gnome.org/dcbw/2010/07/15/not-a-jackass-episode-1/

Sure enough, using the networkmanager daily PPA (https://launchpad.net/~network-manager/+archive/trunk) made the irritating logs go away. Wireless hasn't been unstable yet, although I've only been running for a few minutes at this point.