For a rather good overview of the legal issues (yes, I'm biased, as I am quoted in this), see http://arstechnica.co.uk/business/2016/08/public-wi-fi-forget-the-scare-stories-read-this/
For a rather good overview of the legal issues (yes, I'm biased, as I am quoted in this), see http://arstechnica.co.uk/business/2016/08/public-wi-fi-forget-the-scare-stories-read-this/