Unfortunately in the U.S., thanks to recent changes in the anti-terrorism laws, accessing
any computer system you do not own, without explicit permission (having an open WAP is not "granting" permission), will land you in jail, if caught. We've no-doubt all heard the story about the
priest who was busted for accessing the public library's wireless network from the park bench outside the library.
Which is somewhat ironic, because Intel is pushing their "Centrino" technology hard, with advertisements that show exactly this kind of behavior. It also means that going into any Panera Bread location, Starbucks, or other spot where there is publically-accessible wifi, puts you in jeapordy.
If you do not have specific, explicit permission (i.e. with a username, password, login, or signed contract of some sort), to access the computer (and this includes "computing devices", such as routers, WAP routers, and other similar "computing devices"), you will be nailed.. eventually.
Title 18, Part I, Chapter 47, Section 1030 is pretty clear on the issue. There is also an enlightening
article at SecurityFocus on the matter. What is ironic, is that the
Washington office of the FCC provides their own public wifi hotspot, and even encourages people to use it! The City of Philadelphia is even considering turning
135 square miles of the city into a $10M public wifi network.
This may or may not be lawful, but it is happening quite a lot. Having your laptop or PDA confiscated indefinately, while they figure out what law to
really throw at you, is not a productive use of time. Is
everything on your hard drive 100% legal? No incriminating emails, images, software? The qualification of what is "illegal" and what is not, is much broader than it used to be. Its not worth the risk.
Our present government currently considers "Warchalking" to be a
threat to national security so its best to play on the safe side for now, until the rest of this mess gets sorted out.
"Declaring things that clearly aren't terrorism as terrorism is terrorism!"
-Me, 2001