No answers yet. Hmmmm
I asked an engineer here at work and he didn't seem to really know either, but said they would "reset" them if they could. That doesn't quite answer it for me, as I know there would have to be some NGS forms to fill out, etc., etc., etc., before that could be done. Oddly enough, he was unaware of two (of three) benchmarks located on our company's property! And to add more of a twist, those marks are on a piece of property we were thinking of developing a year ago, and even had plans drawn up for the development. Those plans were only sketches though, so it is quite possible nobody even really walked the property or looked at a USGS map of it.