Yes, the American Indian burial grounds should be left alone. It is a simple matter of respect. The burial plots where we place the bodies of our dead are respected by citizens, why should the native Americans receive different treatment. They are human beings whose traditions should be respected as much as anyone's.
In most cases, I think that any ground where human beings are buried should be left alone. Only in a case where there is an extreme need, or, there is a danger to the public should human bones be excavated. To disturb a grave site for say a housing project, or a shopping center is not necessary.
American Indian burial grounds should be left alone. This is because we should always respect the dead, and not move or disturb them. While often after many years cemetery contents get moved to new sites for development, especially in large cities, if it can be helped we should never actually do this.
American Indian burial grounds should be left alone, just as Christian or Jewish cemeteries should be left alone. Digging up the dead and moving them about is just in bad taste. It may eventually become necessary to start relocating bodies (especially in the crowded Northeast) to reclaim valuable land. However, American Indian burial grounds should not be singled out any more than other burial areas when that time comes.