I was thinking the opposite, what better way for a Western spy to gain access to the Russian Federation than to show up with an old expired Soviet passport and claim Russian citizenship?
What Western spy? Our last known successful American spy who penetrated the Kremlin was Morris Childs, a former Soviet operative/Communist Party USA secret leader from Illinois/Chicago, etc (See: John Barron, “Operation SOLO” re America’s man in the Kremlin and Havana, about 1995.
We have been incredibly inept in penetrating the Soviet Union, Red China, No. Vietnam, No. Korea or even Cuba.