stealing internet?

The BBC recently reported that a man in London was arrested for using someone else's wireless internet service. They brought up all kinds of questions about the morality of such an act. After all, if someone is pumping out a wireless signal without any sort of security to ensure that nobody else can use it, is it really stealing? Aren't they essentially giving it out for free?

What's the difference between this and a radio station deciding that they want to start charging their listeners, but fail to put into place any sort of access restrictions?

Personally, I think it' a joke. Sure, it sucks if someone hops on your internet connection and start downloading a bunch of stuff, all the while clogging up your internet connection. But who gave you permission to broadcast your wireless signal outside of the boundaries of your computer area? If you're transmitting into their home or into a public area, without any ind of access restriction, then it's your own fault. Plus, I'm still not convinced that all of this wireless stuff isn't going to end up causing some sort of health problem over the years. Scientists claim that the signal strength is too weak, but I would suspect that it's too new of a technology for us to really know the results of prolonged exposure. What gives us the right to broadcast a poentially harmful signal into areas of the unknowing?