Well the warning is because CG Wi-Fi is non-encrypted allowing anyone to hack in and piggy back on your signal, Same for McDonalds, and .. Well, most all public wifi, If you do not need a Pass code of some kind to connect and get an IP, then it's non-secure.
That said..... I've never had any cause to think that has been a problem
But only ONE CG I stay at has the kind of people I would suspect of hacking. and in that CG.. Well... I have my Cellular Data.
I'm also getting to the point where I don't do much via Wi-Fi any more (Banking that is) . But that's has nothing to do with this thread, Just simplifying my life.