Well, technically you should then block people from these countries irrespective of where they reside. They have extended families back in their home countries,

Well, technically you should then block people from these countries irrespective of where they reside. They have extended families back in their home countries, so the spooks can still lean on them quite heavily, and there's nothing they'll be able to do. This is why I refused to obtain a DoD security clearance when my job needed me to: I go to Russia to visit my family every 2-3 years, and I don't want to be in any way valuable to their intelligence services or the like, nor do I want to put myself or my family in danger. All of the above is in spite of me having spent most of my life in the US by now. IMO a better solution is for nobody to have permanent access, and granting it on as-needed basis, with a full audit trail. It's not perfect, but it's a heck of a lot better than the ineffectual geography-based blocking that you are implementing.