The game for free WiFi in commercial settings has changed quite a bit in the last few years.
EverBank Field has an expansive WiFi network that is "free" during the games or special events. However, the provider is collecting large amounts of usage data to get information on the fans who attend.
Starbucks, McD's, B&N all collect copious amounts of user data when you use their free WiFi. Where you browse, what version of software, what kind of phone or tablet you have, its pretty comprehensive short of loading any software on the device.
While there are hotspot providers for the Ma & Pa shops that place ads and subsidize their bandwidth costs to some degree, I would surmise that these local shops have simply turned on the guest network feature on their ATT or Comcast Business link.