Private collections of antiquities have been a concern of mine since i first learned of the great rush for Egyptian artifacts at the very early stages in the life of Egyptology. My concerns:
1) Acquisition - Some (not all) of these collections may have items acquired on the black- market and therefore could have been looted from tombs/ temples within Egypt.
2) Provenance - Many items within these collections may not have arrived through meticulous archaeology and therefore the locations of their finds, and the dating layers are lost to those of us who need this information. Many museum collections around the world have many tags which suggest "provenance unknown".
3) Preservation - Are 100% of the artifacts held in private auctions given the correct conservation, using non- evasive techniques (particularly concerning mummies)? I doubt it.
4) Shared knowledge - Is there a worldwide database of all the Egyptian artifacts in private collections? See this story posted by Paul Boughton on Egytotology News Network (these items were found by accident).
Without the ability to study artifacts, information is lost. Every scrap of information is vital- everything. We are not talking of course about gold. Gold is a distraction many Egyptologists could do without having to inform the authorities and stop working at a drop of a hat. We are talking about anything with hieroglyphic/ hieratic/ demotic inscriptions. Even seemingly insignificant wall fragments may be the key to understanding a scene.
At this stage i must add that not all private collections are illegal. Not by far. My concerns lie in those undocumented collections - hidden away in private where i feel time is absolutely NOT on their side.