Cold War example
In July 1970 I observed a German civilian (grey Opel) parked off-base at the west end of the Ramstein runway every afternoon when I cycled home from Kindsbach. The driver rarely saw me approach so I clearly saw his notebook and binoculars. I asked my Dad (Canadian Air Force Lt. Col.) why the Americans allowed it and he replied: "Maybe we want them to know what we've got". As I learned much later, the F-102 and F4-4E were much more reliable than the kit used by the "Nasties". Deterrence.
They (Russia and China) are independant from the US.