I wouldn't be so quick to dismiss the possiblity that their beliefs are sincere. My mother spent the last 10 years of her career dealing with native american cultural resource issues for a major federal agency in the West, and thus got to know members of quite a few tribes very well. Concern for sacred, historical sites was quite real for many native americans, independent of using such concerns to get cash (which was also a motivation too, to be sure).
I'm not sure many believe in the literal truth of ancient religions, but, many do sincerely care about sites of traditional spiritual significance being protected. And the Indians certainly aren't alone in that. Just imagine the outcry if the federal goverment proposed plunking an observatory right in the middle of the Gettysburg battlefield.
Space/Science » in reply to Probably a simple shakedown.
Not quite so cynical