1) on-site looters or tombaroli,The archaeological record may be endangered most by the fifth invisible column whose members are within the archaeological community. Muscarella illustrates the ways in which professional archaeologists facilitate Plunder Culture, suggesting that attitudes to collecting and collectors reveal that the "discipline of archaeology has no comprehensive sense of itself, no unclouded self-knowledge, no awareness of its moral and academic weakness".
2) local dealers and smugglers,
3) commercial antiquities dealers,
4) collectors, private and public (museums and universities).
Muscarella urges archaeologists to reconsider the consequences of their professional, academic, and personal associations, and to those who consider themselves clean, he urges active participation in the protection of the archaeological record from the commercial depredations of the dealer and collector. I would say Muscarella's paper should make thought-provoking reading for all those supporters of the PAS out there in the UK. Are they "Fifth columnists"?