KILKENNY -- When my neighbour turns on her laptop while sitting at her kitchen table, her XP Pro system finds my WLAN and asks whether she wants to connect to the available network. So she occasionally does, especially when out in the back garden under the sun. Does she incur a liability when connecting to my open WiFi node? There is plenty of talk in the Irish tech press about securing your infrastructure but as anyone with an eye to the cheap side can vouch, you can find open WiFi nodes sprinkled all across Dublin. Many of them come courtesy of Eircom, the largest Irish telco. Attorneys have started grappling with issues related to open access and those burning questions will bounce around on Irishblogs as the popularity of wireless technology continues to increase.
Robert Hale has taken an American perspective and written a paper that explores several theories of liability involving both the accessing and operating of wireless Internet, including the Computer Fraud and Abuse Act, wiretap laws, as well as trespass to chattels and other areas of common law. It's worth reading, especially if you plan to hook up to free WiFi nodes while in taxis crossing large cities in the US.
Robert Hale -- "Wi-Fi Liability: Potential Legal Risks in Accessing and Operating Wireless Internet" in the Santa Clara Computer and High Technology Law Journal, Vol. 21 at http://ssrn.com/abstract=692881 (175kb PDF).