westdelta, I invite you to dig up those articles. The stories of supposed problems when WiFi squatting get much press--in no small part because the vendors of general wireless service, like Verizon and ATT, encourage the spread of these articles. When carefully checked, they virtually always fail to pan out for US cases. (Europe is somewhat different.)
There are three very common stories. Two involve Minnesota. One involves a big-box home supply store, where the actual prosecution was for hacking the store's database, not free-loading off their Internet WiFi. The other Minnesota story involves some schmuck who pled to a minor charge rather than fight for the dismissal he was entitled to. The third common story involves an over-eager cop on Nantucket about 5 years ago who chased off people using the library's FREE WiFi from outside, instead of inside, the building.
While various blogs and forums devoted to Internet related topics blather on endlessly about whether it's "right" or "ethical" to mooch open WiFi, it's very hard to say that it's clearly illegal. (Yes, this is an open challenge for anyone to cite California or federal law making WiFi mooching illegal.)
Realistically, there is as much chance of being successfully prosecuted for "theft" of WiFi Internet access as there is being prosecuted for reading a novel on the street at night using the spare light from someone's post lamp. The main reason is that securing the signal is so easy that it's fair to say an unsecured signal is an invitation for use, just as a park bench adjacent to the sidewalk is an invitation to sit.
There are many things that can change this--including any form of hacking (either past even the most basic form of WiFi security or into the WiFi provider's computer) or some other indication that casual use is not welcomed. I wouldn't, for example, use a WiFi signal named "private" or "stay_away".
Additionally, the cautionary aspect mentioned above is a real concern. Not only can the person running the WiFi try to hack your computer, he can trace your Internet steps. Most significant transactions (bank, etc.) are hopefully encrypted, but you may not want someone knowing that the same person who posts here as "SpecialDeltaRacerGuy" also spends a lot of time at www.speedboatsex.com .
There's also the ultimate kicker: Even if someone on the Tiburon shore figures out that their WiFi is being used and they don't like it, if they are too lazy or incompetent to secure their WiFi, how are they ever going to figure out who YOU are?
BTG