Hi Rick,
I do not think battle field pick ups really come into the "questionable area" The sacking of the royal palaces of Ghana and Benin amongst others on the most shaky basis must fall into the grey area, where the events were forced by an overwhelming superieur power. The looted palace artifacts were sold on the open art market to offset the expenditure. If I was in charge of the British Musuem I could still not sign the paper.