its a nice idea, i'd like that also but don't know of such fb-functionality. in my case i have no use for the permissions.
maybe permissions with an expiry date would be great.
Revoking Login
You can also let people completely de-authorize an app, or revoke login, by making a call to this Graph API endpoint:
DELETE /{user-id}/permissions
This request must be made with a valid user access token or an app access token for the current app. If the request is successful, your app receives a response of true. If the call is successful, any user access token for the person will be invalidated and they will have to log in again. Because you're de-authorizing your app, they will also have to grant access to your app as if they were logging in for the first time.