It's not very complicated to know what's legal and what's not. Was it exported from the country of origin prior to 1970? Legal. Exported with the permission of

It's not very complicated to know what's legal and what's not. Was it exported from the country of origin prior to 1970? Legal. Exported with the permission of the government at the time? Legal. The problem here was fraudulent provenance documents. Ideally, every item that goes up for auction would have its provenance investigated. In practice, that's too expensive for the auction houses.