Go into your network settings and select the network. Press the little blue button to the right to see that network's options. You should find that it already has a DNS server, IP address, etc. Where it says "auto join" - turn it OFF.
Close settings and it should show up the wifi icon at the top. Open safari, agree to whatever TOS, and you should be good to go. I've been looking for this solution for a year and just discovered it myself tonight, so hopefully this post will help others out there.