I heard that story of authorities blocking some tunnels and cataphiles removing the blocks from someone who went down there; I don't know how widespread it was.
It's a common game of cat and mice, still "played" to this day. When they can be bothered enough, authorities will fill a section of a gallery with concrete. And, in turn, when cataphiles can be bothered enough, they tear down a piece of an adjacent wall and dig through the dirt on the other side to go around the blocked section. I've also seen crawl holes dug under 1m-or-2m-thick rubble walls.
Amazing to see the length people will go to :')