Nathan Elkins has published his thoughts which he's been blogging about for some time in response to the views of the commercial "numismatic professionals" who are trying to undermine preservationist measures apparently with the full support of the IAPN and PNG: Nathan T. Elkins, "Ancient Coins, Find Spots, and Import Restrictions: A Critique of Arguments made in the Ancient Coin Collectors Guild's 'Test Case'," Journal of Field Archaeology 40.2 (2015): 236-243. I'd like to see them answer in the same tone - citing their evidence.
Abstract: The Ancient Coin Collectors Guild (ACCG) has launched multiple legal challenges aimed at undermining import restrictions on ancient coins into the United States in bilateral agreements with foreign countries. One key component of the ACCG's argument is that the State Department has inappropriately restricted certain types of coins according to where they were made rather than where they are found, as mandated by the 1983 Convention on Cultural Property Implementation Act. Although the ACCG has thus far been unsuccessful, it has not been pointed out that existing import restrictions on coins, in fact, have been written to include coins that tended to circulate locally and that are found primarily within the borders of the country with which the bilateral agreement is made. The ACCG's argument is thus on shaky ground. As the ACCG continues to press ahead with new litigation, it is worth drawing attention to realities and probabilities of ancient coin circulation as they pertain to protected coins