Wi-Fi location affects online privacy behavior. Does sitting in a coffee shop versus at home influence a person's willingness to disclose private information online? Does the on-screen appearance of a public location's online 'terms and conditions' have an effect? According to researchers, the answer to both questions is 'yes,' especially if the user has a tendency to instinctively distrust public wireless networks. Source 5c.
I generally do not use public access wifi because you don't know what's happening to the data being sent through their wifi signal.