One more time, it doesn't matter if it's copper, glass, or radio, connecting to a network without permission is a felony in all 50 states. If you don't know if it's a free hotspot, then it probably isn't. Using some one's light isn't a good analogy for this. Sure it's still a em field, but light is a one way street. If you stood outside someone's bedroom window and shined a flashlight into it, sure as hell the police would be called and you'd be given a ride with them.