It appears that Greece's two major coin collections, those of the Alpha Bank and National Numismatic Collection, were subject to attack during the recent spate of rioting, but they are probably safe for now.
First, the ground floor of the Alpha Bank was set ablaze, but hopefully the coin collection on the eight floor of an adjacent building is still secure.
Second, there was also apparently an attack on the Government Numismatic Museum in the old Schliemann mansion, but hopefully the collection is safe behind security.
Recently, the State Department Bureau of Educational Affairs and US Customs imposed import restrictions on undocumented ancient Greek coins. Any coins that are forfeited under these regulations will go back to an uncertain future in Greece.
Archaeological bloggers remain in a state of denial about the implications of all this. And the State Department and US Customs presumably could care less about what they have wrought.