You would be amazed at the number of people who fire up their access point with NO WEP.
You're probably familiar with "wardriving," the practice of identifying and cataloging access points. If you haven't already, you can download a copy of "netstumbler" at
www.netstumbler.com that will log all the access points.
I can sit in my apartment and pick up 7 different networks, including somebody's Apple AirPort. . . pretty cool.