To all those asking how can something like this be missed in testing, the answer is: simply, because it is not an OS issue per se. As it was explained earlier in the thread, iOS relies on pinging a certain page on apple website to determine whether your network requires additional authentication. Since the page is currently removed, the OS is not getting the response it wants and shows you the log in window, displaying the page that normally would contain the authentication forms. Since there is no such page, you just get a 404 from Apple's own website. Nevertheless, this still sucks. Parhaps one way to try tor esolve this would be to actually create a guest network reuqiirng authentication.