Interesting. Any discussions I have had never got anywhere near the points you both mention, but it would seem that it comes down to Rex’s earlier point.

Rex posted: Might their subsequent work be classified? It ought not to be, if they aren't currently working for government, it is not a reproduction of their for-government work, and doesn't use classified materials.
That this is the way the situation applies makes sense to me. I know any number of people who publish who obviously had very high clearance at one time or another, and they may still have their clearance for all I know, for it never occurred to me ask them about this.