c6h6o3,
That's apples and oranges. Washington DC has had a tripod by permit law for well over forty years. I was being chased off by the park police in 1966. It has nothing to do with 9-11 or political climate. The BLM rules have nothing to do with DC metro and park police. Those so called goons are enforcing a law that they had nothing to do with but is in affect in their jurisdiction. You could always get the permit or petition the government.