I ran across this "Prohibido Volar Drones" / "Flying Drones Prohibited" sign at about 11,000' MSL in the El Rosario Monarch Butterfly Reserve in the mountains of Michoacan, Mexico a couple of weeks ago. The reserve is one of the winter homes for millions of Monarch Butterflies that migrate southward from North America every year. It's a wonderful place, every bit as reverent and sacred as any cathedral. I had no argument with the prohibition. There are places where drones, automobiles, dirt bikes, boomboxes, pets, and even loud voices just are not appropriate.