“The best way to keep yourself safe is to use your own Wi-Fi connection, if you’re able to set up a personal hotspot, or to ask employees (such as baristas in a coffee shop) which network is theirs. A free connection that pops up while you’re on the go might just be too good to be true.”
Just because there’s a wifi signal available, doesn’t mean you should connect to it. Verify the network is one you can trust, and even then don’t do any banking over it or anything like that over it, ok? Go read the article, it sounds like an interesting experiment.