I use a public WiFi in my office building to read iPad (iOS7) every morning.
On iOS6, the device connected to WiFi. As soon as I accept the Ruckus Wirelss conditions, I was connected to internet.
However, since upgrading to iOS7, the iPad sees the Ruckus Wireless network and connects to WiFi. As soon as I accept the conditions, the WiFi disconnects and I have to select the network to have WiFi and internet access.
The iPhone has the exact same behavior
This could be any number of things, Unfortunately, as you won't be able to provide additional info we can't really provide an answer. Best bet is to contact the provider of the public wifi and if they determine it's affecting more users. they can contact us for support.