I had lunch with Gregory [1] today, and the topic of wireless access point security popped up. I mentioned that Bruce Schneier [2], noted computer security expert, leaves his wireless access point open [3], and Gregory had to ask why. I didn't have the answer at that point, but Gregory, you can now read the article (as well as some discussion [4]).
[1] http://corsair2.livejournal.com/
[3] http://www.schneier.com/blog/archives/2008/01/my_open_wireles.html