I'm afraid I disagree with you. Not knowing would be worse. The people involved are highly motivated to prove that their oral tradition is based on fact.
And besides, Nikwasi Mound is in the middle of large town, with little or no cover. A looter is highly unlikely to pull up his backhoe and start in.
If you are actually concerned that GPR will become the new tool of looters, they seem to be doing just fine with shovels, backhoes, and long metal probes.
Something is not right. This message is just to keep things from messing up down the road