Well there’s indeed another source of local income there.the search teams in Vietnam and Laos found that locals were "seeding" alleged crash sites with teeth and long bones from locals in the hope of prolonging the gravy train. Same as for the mine clearing teams.
The Americans treat each site as an archeological dig. They set up big sieves etc to look for fragments. They use a lot of local labour. They dig in the dry season which is often a comparatively slack time in rice farming.
It’s interesting that the American records are very good. We found their bombing data to be very accurate, and the book ‘Where we were’ is an encyclopaedic record of all military positions. They also have a pretty good record of the general area of any aircraft crash.