I'm not sure what all of the fuss is about. They didn't somehow obtain a copy of Google's real certificate; they made a fake one with the same contents, but not signed by a certificate authority your browser trusts. Your browser erects the standard "woah wtf" alert. There is a ton of infrastructure built into your browser to make sure you are aware of this.
I suppose the main reason to be concerned is that, sadly, many people will click through this; generally, though, they are the same people who will download random software and install it, join untrusted wifi networks, click on attachments, etc etc -- in other words, they are already victims of clicking-before-thinking or clicking-without-understanding.
This is less horrible than silently modifying pages, injecting JavaScript, etc -- at least you get a warning and can go to a non-ssl page and pay for your wifi (and then use a VPN if you so desire). It isn't just GoGo that does this. Various other public WiFi, such as hotels, airports, etc, often do things like this as well (though usually just to extract payment rather than selectively block certain sites).