There are lots of ways to secure a wireless connection. One of the more popular ways with business WLAN's is to not secure the wireless connection at all, and run everything over a VPN connection. The VPN traffic is encrypted and is therefore sniffer safe. Authentication is left to the VPN.
However, all the one's I've seen have a splash screen that greets the casual hacker with threats of prosecution if they continue beyond the initial connection. You're expected to fire up your VPN software, or connect via SSL/TLS to an obscure authentication server. If you don't know the name of the server, you don't go anywhere. I guess someone is setting up a similar system but without the splash screen warning.
You can usually get a clue as to who owns the system by the SSID. If it's your local police department or government, I would tread carefully.
There are also various services that provide VPN terminations. I blundered across:has a Flash movie of how to setup their VPN client or XP at: shows roughly how it's setup. Once connected to the VPN server, all the internet traffic goes through the default route at the terminating VPN server, instead of throught the default route of the hot spot or corporate access point.