While I agree that it is a bad idea to use any private WIFI without permission, I wonder if there is more to this story. I wonder if this is more than just the guy checking his email. If he was just checking his email or looking at cnn.com, then that story is indeed very troubling.
Windows XP will automatically connect to an open network if it finds one. More than one occasion my laptop has found and connected to a network automatically and started downloading Windows updates or McAfee antivirus updates. This has happened sitting at red lights or stopped at a McDonald's in a city somewhere. Under that law, you could be prosecuted for that too. Or Microsoft could be sued for making XP a party to the 'infraction'. There is usually no way to tell where the network is coming from. For example, here in Charleston, the local Steak Escape restaurant offers free WIFI, but their SSID is 'linksys'.
Sounds like a law that should be challenged or at least clarified. Especially if the guy just stopped to check his email after the XP dialog box went 'ding' saying there was a connection available.
I will say this, that at least on the Linksys router I have here at my house, enabling encryption is NOT easy. I'm no computer newbie either. I could not get the client computers to recognize the key I assigned and after several more tries and different keys, I finally just gave up and opened the router again so I could use it. I wouldn't assume that most everyone who has an open router is doing it intentionally.
That said, getting permission to use a connection legitimately is usually easy. That and the fact that there are an increasing number of low-cost and free hotspots out there make it uneccessary to drive around residential areas looking for wifi.