I managed to score a copy of the infamous "Last Measure" web application, loaded it up on a spare machine and made a "Last Measure AP" with some wireless routers setup as "FREEINTERNET" and "linksys". This car was always coming by using the open wireless in the apartment I was staying at so one night, I put up the 2 Last Measure APs and took down the apartment wireless by doing a DHCP release. All you see, from the laptop glow within the car, is a guy throwing his hands up, furiously typing and the driver taking the laptop, doing the same thing but finally the passenger slammed the lid shut on the laptop while they drove off.
This was also near a school where women with their iPhones and Blackberries would use open wireless.. too bad I'm a nice guy and didn't sniff for Facebook / email logins..