No, I don't, because I worry about my own security if I do so. If you connect to someone else's unprotected WiFi network and you don't know who it is, you could be exposing yourself to a huge security risk. Maybe it's a hacker who is logging all your network traffic and who wants to steal personal information from you.
I remember a few months ago that security at the airport almost caught someone doing something like this: He was sitting somewhere with a laptop, offering a free WiFi connection, and when people got suspicious and wanted to approach him he quickly shut down his laptop, the network disappeared, and he walked away.
Beware of unprotected WiFi networks. [ June 30, 2008: Message edited by: Jesper Young ]