Consider: you can't repudiate your fingerprints. So all the Chinese or Russian authorities need to do is to look for these fingerprints on folks entering the country and they can identify anyone with a US security clearance -- and in particular look for the other characteristics indicative of a CIA or other human intelligence operative. Such as, oh, a set of prints matching someone with a US security clearance attached to an authentic but definitely-not-in-the-same-name passport.
Spies are going to be so much a thing of the past ...