Connecting to the internet via an unsecured wireless connection

The BBC has a very interesting article on connecting to the Internet via an unsecured wireless connection, is it wrong to do that? The person is the one offering the connection for free, but taking the internet from him might slow down his connection!
I have a wireless connection at home, it is a secured one but I always check the logs of the router and check the connected computers, I also turn off the router when I am not using the internet, I do that because I know that my connection is secure and connecting through it involves hacking and this would be stealing and I would make the person stealing my connection pay for this (info on how to do that later).
But what if I left my connection unsecured? Connecting through it would be very simple, the person doing it would be taking something that he isn’t paying for but this connection is available for him!
I never found an unsecured connection so I never had the chance to connect to one, but I am pretty sure that if I ever found one I would at least test it’s speed but would never check my mail on it, maybe a person is offering this connection for free and monitoring the traffic to take info! I think that everyone is responsible for his connection and if you leave a door open you can’t blame someone for taking a peak inside!

Router WiFi