I use public WiFi in cafes and libraries all the time, but I would never use a public computer there. I bought an HP Netbook, and a Logitec keyboard for my phone, and both of those allow me to use my own equipment. Neither of them cost much money, so I can't see the point in using a public computer. The only time I have done it is to assess a library printer, and you need to scan a library membership card to do that.