We have added a "Remember me" functionality to the hotspot login pages.
You can hide this option from the Control Center which is especially useful when you are using desktop computers in your location and you wish to avoid that one user may log in with the previous user's details. You can turn this option OFF in the Control Center > Edit location > Splash Page Settings > "Display 'Remember Me' checkbox on Login Pages" checkbox.
If you are using custom skins, you need to update hotspotlogin_loginform.inc.html and main_combined.inc.html for combined login pages.
iOS devices and now the latest OSX Lion brings up a login popup safari when users connects to a wi-fi network and the OS cannot ping apple.com, this is how it knows that you don't have a full access to the internet so it brings up the splash page immediately. Unfortunately this behavior has its disadvantages. First, this is not a regular Safari browser and cookies are handled differently so the "remember me" functional will partially work (if you are using iOS devices), or won't work at all (if you are using Lion where the login popup doesn't handle cookies at all). Another thing is that when the user logs in, the popup disappears and the user won't see the popup which we display for the user with session statistics and logout information.
We have a knowledgebase article about this issue here with a "solution".