Open wireless networks are part of a socially just technologically advanced society. They allow access to mobile users and also improve anonymity, including that of the networks' owners and primary users.
Many companies run open wireless networks to attract customers, a practice that is commonly found in coffee shops, bookstores, and areas with large numbers of commuters (e.g. transportation hubs, hotels, and highway rest stops). Some municipalities have created municipal wireless networks as have other communities of like-minded individuals.
It's being nice.
Never go in against a Sicilian when death is on the line!