The Impact of Returning Antiquities to Italy

I have been working on the impact of the returns to Italy from North American public and private collections as well as auction houses and galleries. The count now exceeds 350 items, and is valued in (at a conservative estimate) the tens of millions of dollars.

How did museum curators and directors support these acquisitions? Were private collectors unaware of the issues? And what did those involved in the market know about sources and collecting histories?

How far have due diligence processes been strengthened and tightened?