"Demonstrably stolen": where does the burden of proof lie?

Sir John Boardman (in Eleanor Robson et al. [eds.], Who Owns Objects [2006]) recently suggested that current legislation over the protection of cultural property has created:

"The denial of the right of persons or museums to acquire antiquities which are not demonstrably stolen or the result of plunder, since most are only so deemed, not proved."

What does he mean? Does somebody have to be present at the time the archaeological site is raided?

Nigel Spivey has pointed out the problem with that course of action by quoting Professor Mauro Cristofani.

"And what will you do ... when staring down the barrel of a sub-machine gun?"

Is it enough to have photographs or Polaroids of, say, Athenian red-figured pots that are still covered in dirt? Does that imply that the objects were fresh out of the ground? And, if they were not excavated by archaeologists, can they be considered to have been "demonstrably stolen"?

Or what about a site where the bases of statues survive in situ but the bronze sculptures have been removed - and form part of museum and private collections? Have they been "demonstrably stolen"?

So if an archaeological object appears in an auction house, gallery, museum or private collection without any previous history we can be suspicious. Research by Chippindale and Gill pointed out this phenomenon for two private North American collections: Shelby White and Leon Levy; Barbara and Lawrence Fleischman.

The fact that the Italian government has been been able to make the case for the return of some of the Fleischman material (now in the Getty) underlines the point. And the Italian government is reported to have made approaches to Shelby White.

Were the Fleischmans and White/Levy wise to acquire antiquities which could not be shown to have been in circulation before the 1970 UNESCO Convention? Perhaps the question to ask is this: were they badly advised?

This debate is not about denying rights. It is about protecting cultural property.