It's easy to block you out if someone notices something weird with their connection. In short, you need a service provider to connect to the internet. To get from one point to another, you connect through a series of machines, using cables or other equipment that someone ultimately "owns" the rights to.
Also, if you don't think there's a better option for you, I don't know why everyone is recommending that you connect to an unsecured wireless network. It's probably no better than yours. Better make sure your own network is secure first of all.