This is a little off the main question but bears on some of the other comments re:natl. Parks. I was in DC last year and wanted to take a shot inside the train station. I was off in a corner next to a potted plant totally out of the way but a guard came over and said, "No tripods". I couldn't disuade him. Then later on I was out side the Hirshorn Museum on the Mall and a guard came out with the same request. I had to move back to the public sidewalk to appease him. Still later I wanted to take a shot in a metro station and set up the tripod behind a bench again out of the way and was told to move along. The next day on the lower entry "patio" of the Supreme court bldg another guard came over and wanted to know if I was going to sell the picture. I can undersatand having dozens of tripods in the middle of pedestrians but 1 person ???