Are there evidence it is really happening? Which open wifi network are left in residencial neighborhood? My neighbors aren't tech savy yet they use the wifi configured provided with the router which has a passphrase. I believe even in McDonalds you get the wifi password only upon purchase in the receipt. Most open networks I still encounter are in big stores such as IKEA or airports and you still have to register to connect. I doubt the signal woukd reach even the closest houses anyway.