You're right, Spring Social doesn't support that. Spring Social only knows whether or not the user has connected with Facebook and then, using that connection, you can fetch the user information. But whether a user has created a connection and whether or not they're logged into Facebook are two different things.
The client-side stuff deals with this easily by considering whether or not a certain cookie value is available. I suppose it's possible for the server-side to do the same thing...and you might try using Spring Social Facebook's @FacebookCookieValue annotation in a Spring MVC controller to see if it gives any clues as to when a user is logged in or logged out of Facebook. I've not tried using @FacebookCookieValue for that purpose, but if you try it out please let us know here in the forums what you find...I'd be interested in knowing whether or not it can tell you a user's logged-in status with FB.
Spring Social Project Lead