In some coffee shops that offer free WiFi (for instance Starbucks), I have noticed that attempting to use HTTP or HTTPS fails unless you accept a notification (on Windows at least) which looks something like the image below:
Attempting to open a webpage causes the browser to be momentarily highjacked by a 'httpclient' which redirects to one of the coffee shop's web pages (for instance, below). All subsequent pages opened appear to work normally.
My question is if this has any bearing on information security. It feels as if one of the coffee shop's machines is acting as a man-in-the-middle. Could this machine, if doing so, snoop on traffic?