FB recently introduced Enhanced Auth Dialog which solves the problem you mention about.(https://developers.facebook.com/docs/opengraph/authentication/ https://d

FB recently introduced Enhanced Auth Dialog which solves the problem you mention about.(https://developers.facebook.com/docs/opengraph/authentication/ https://developers.facebook.com/docs/opengraph/authenticatio...) It allows users to remove permissions such as posting to facebook. Unfortunately it is opt-in for apps.