I question some of these South American burial studies - they're only going back a few hundred years, some of them. How long do we have to wait before some future professor wants to dig up your own family grave?
Seriously, what's the cut-off? 400 years? Are the Jamestown colonists are ready to be made travelling exhibits by now?
I worked on a cemetery from the 1800s in CT. In that case they were unmarked, in the middle of a sand and gravel operation, found by a machine operator.
He thought it might have been a murder site, so the police were called in, then once they determined the age, we exhumed the bodies, did some analysis, then reintered them in a nearby marked cemetery.
But I guess this is a different situation, since these will probably be studied for a lot longer period. I dunno, graves/burials are always political flashpoints. One of the reasons I got out of Archaeology actually.