This is what I dislike most about free wifi. It's completely lacking in security and most are not aware of the issue. the use of mobile apps makes it worse. At least with a browser, the browser will warn if something suspicious is happening. But there's no way for a user to know if a mobile app is using https and using properly (not ignoring certificate errors).
Question:
How secure is LinkNYC Wi-Fi?
Answer:
The LinkNYC Private network is one of the first
free municipal Wi-Fi services in the country to
offer an encrypted network connection between your
device and the hotspot, securing all wireless
communications between devices and the Link.
I'm not sure about the feasibility of the encryption protocol but as an anecdotal note, a buddy of mine worked as a software engineer at Control Group and I almost considered interviewing there when I was looking around recently, so they are investing in a significant number of engineers at the very least.
"The full network will install more than 7,500 public hubs throughout the city, each replacing a pre-existing phone booth. Once completed, the hubs will also include USB device charging ports, touchscreen web browsing, and two 55-inch advertising displays. The city estimates that ads served by the new hubs will generate more than $500 million in revenue over the next 12 years."