In fact, the primary motivation of locking down an AP with a WPA password, from an infosec perspective, was NOT ABOUT stop people from using free Internet conne

In fact, the primary motivation of locking down an AP with a WPA password, from an infosec perspective, was NOT ABOUT stop people from using free Internet connection, BUT to harden against the technical limitation of WPA/WPA2 - the protocol, by design, CANNOT offer encryption on an open network, widespread usage of SSL/TLS was only a recently development, it used to be that you cannot run a open AP without COMPLETELY COMPROMISE EVERYONE's security and privacy on your network, INCLUDING YOUR OWN. The better way of doing it, is creating a separate AP, setting up a password and showing it publicly, then the attacker at least needs to intercept an individual handshake before being able to decrypt a portion of traffic. The even better way is WPA-Enterprise, but... In short, the Wi-Fi standard itself unnecessarily forces everyone to make a hard choice between security and openness. Fortunately, and hopefully, the awakened situation is going to be solved, WPA3 supports encryption on an open AP. Also, WPA3 offers forward secrecy, the traffic cannot be decrypted by passive monitoring unless the attacker is also a Man-in-the-Middle. BTW, as tyingq said, copyright is a factor, but I think laws in generally are a bigger problem. Under the laws of many jurisdictions, the Wi-Fi user may be responsible for all the legal consequences of other people who is using his/her Wi-Fi. Routing the guest AP over an anonymous VPN connected via Tor may be a solution to the legal challenge, but a legal issue needs a real legal solution. If you are interested in sharing your Wi-Fi, read https://openwireless.org/ https://openwireless.org/