When I was a kid I came up with a name for the group that snuck in and set up those signs, “Polite People for the Cessation of Byway Maintenance”. They always put their protest signs up a respectful distance away and always just the one in each direction, thus the polite people part.
I know I was assuming that the Russians claimed that they were nuclear bomb proof, at least for the 30 seconds that I knew about them before I read this thread. Seeing the picture I didn’t believe that they were in in actuality.