I heard that is not illegal. If they wep it and you crack it, it would be, but if its open its considered public. Because it uses the public 2.4 ghz freq or 5 gig freq. It would be like watching someones big screen tv from the sidewalk. They left the blinds open so its free to watch. But when they close the blinds and you break in to watch their tv its illegal. I read up on it when I was building my long range wireless project. Because I was going over 33db I could not wep it because it is a public freq. But for sure if you log on an open connection and then view their computers files you are starting to breach their privacy and that is unlawful.