For a good review of the problem, read Tony Hilerman’s Thief of Time. It is a great murder mystery in which Lt Joe Leaphorn and his sidekick Jim Chee of the Navajo Tribal Police chase pot thieves and archeologists from Chaco Canyon to Bluff Utah and the Smithsonian.
This law will double cover reservations. We all be guilty then just for living among ancient ruins and picking up rocks for slingshots.