Who will pay for this “free” wi-fi? Undoubtedly with massive new taxes on Internet access or perhaps computers. Look at the taxes and fees tacked on to your phone bill for a sample of what is to come.
Ads, just like "free" network TV. You'll probably be routed through a proxy that "helpfully" places the ads in a div on the top or the right-hand side of every webpage you look at. Probably sneakily in a way that is extremely difficult to filter out.