Chip NoVaMac said:
From the routers I have set up in my time, they make it very clear about setting up security to protect your assets. So the ignorance excuse does not work. Again I will state that the law looks at things differently with hard property. I think most courts would be hard pressed with you placing an iMac on your lawn as to if I took it, whether you or I were wrong. The popular excuse of entrapment used against the police comes to mind.
For real answers, seek your lawyer. Supposition has no place in law. For one, comparing a real piece of property to something that radiates radio frequencies is a bit ludicrous.
Additionally, it's pretty easy to discern if someone intends to share their WAP...knock on their door and ask them if its purposely open. If you drive or walk around intentionally looking for WAPs to tap, you're technically savvy enough to know how to locate where the WAP is and ask the owner if its purposely open and if you can use it.
This isn't as vague, law-wise, as people seem to think it is. Just ask a lawyer about your local laws regarding this. Ask if its legal to use a WAP if its open, regardless of where its at. Ask if its legal to use the WAP even though it may not be the owner's intent for it to be open. If you don't have a lawyer, ask anyone that has experience in law and IT. Just because its there doesn't mean you can use/steal/borrow it...this goes for the physical world AND the abstract.
Not everything in life is free, although it may seem that way.
You might also want to remember that there are people out there that deploy fake open WAPs to phish. While you may not pay bills using credit cards when borrowing someone's WAP waves, you may be checking mail...it's simple as all hell to sniff mail account passwords these days if you're not using some type of encryption, as alot of clients send passwords in the clear unless you configure them to do otherwise. And mail is just the start of it.
I'm still trying to figure out why stealing other people's bandwidth is so trendy these days. It's the same as stealing cable, IMO. If you can't go to the WAP owner and ask for permission, you probably shouldn't be doing it. You can also ask yourself, if I drove by a law enforcement office with a laptop and noticed they had open wifi, would I assume its free because its open and use it to check my email? If your answer is 'no', you probably shouldn't be doing it to homeowners who have open WAPs.