We finally reached a final ledge where the uninterrupted granite rose several thousand feet above us to the summit of half dome. And here we found a most unexpected tent (a very nice Bibler single wall tent at that) belonging to the American Safe Climbing Association. It would appear some volunteers had gotten permission from the park to use this area as a base camp to maintain climbing routes on half dome. Maintenance mostly consists of replacing bolts that might be worn or aged.