Beware Free Wi-Fi

It's amazing the lengths that some people will go to in an attempt to steal private data.  Ars Technica has an article that might make you think twice about doing your online banking over an open WiFi connection:
“Open wireless networks are rapidly becoming an important part of urban culture as modern digital nomads increasingly eschew offices in favor of coffee shops. With the rise in popularity of WiFi-enabled mobile computing devices and publicly accessible access points, a new kind of WiFi security threat is beginning to emerge. Security researchers are beginning to note increasing instances of so-called "evil twin" attacks, in which a malicious user sets up an open WiFi network and monitors traffic in order to intercept private data.”
What do you think about people listening in on your WiFi transmissions?  Is this something you're honestly worried about, or do you think this will never happen to you?
Tags:  Free, free Wi-Fi, AR