The people who care about the sanctity of these burials sites are long dead, and they can teach us a lot about how ancient civilizations lived and what kinds of tools they were working with. Now, this is different if there are still people about the area who belong to the belief system of the people who are buried.
Preshistoric burial sites can teach us a great deal about the people who came before us, and in turn they can teach us about ourselves. It is important, however to treat these prehistoric burial sites with great care and reverence for the people who came before us as we would want to be treated the same way.
These burial sites should not be disturbed. Just like any other grave site it is sacred and we should let these dead souls rest in peace and not mess with their resting places. Now whether you believe in the curses that a lot of these places claim to have is irrelevant, just have respect for the dead. Learn from other things and don't disturb someone's grave.
I feel we should leave the graves alone. This is because burial grounds are sacred. Just because there is no living family member to deal with in disturbing a grave doesn't mean we should dig the people up. Rest in peace should be used for the dead forever, not just until scientists decide it is no longer necessary.