I didn't follow the link (darned dial-up), but just the title of this thread pisses me off!
I would think that the petroglyphs in the article would have a "steward," a person or persons who periodically check on them for the BLM (volunteer work). I have a friend and his wife who do this here in the Winnemucca area.
When I lived in the Bishop, California area, I knew of many petroglyphs. I've been on a private tour of the famous Coso petroglyphs on China Lake Naval Weapons Center north of Ridgecrest, California. I've seen some newly discovered petroglyphs north of Bishop in a nondescript area, which required a long walk and uphill slogs through open country with sagebrush.
I've seen a nice set of petroglyphs so mangled by the side of the road; many individual parts were lifted off and taken by souvenier hunters. There is a set nearby, also alongside the road, that is pristine. BLM didn't put signs up there, but did create a parking area and a wood rail fence. It's called "Newspaper Rock."