My sympathy for the Ancient Coin Collectors Guild in the US  is somewhat limited – they want some sort of exemption from, or change of the law regarding ownership of cultural property & seem to be regularly pushing articles to highlight their case.
San Francisco Examiner 
Another hobby it’s legally hazardous to pursue
By: Walter Olson | 08/17/11 6:00 PM
Special to The Examiner
Thomas Jefferson, John Quincy Adams and Ronald Reagan were among the many notable Americans who have enjoyed collecting ancient and historic coins.
Add to their number countless kids awestruck on their birthday when a grandparent presented them with a genuine coin from the Roman Empire to crown their treasure trove of more ordinary Liberty dimes and buffalo nickels.
Unfortunately, you might soon need to add this innocuous pastime to woodpecker-rescuing and
lemonade-selling as activities that carry too much legal risk to encourage in your offspring.
According to Legal Times, “The Convention on Cultural Property Implementation Act, passed in 1983, gives the president the authority to enter into agreements with other countries to restrict the import of artifacts of archaeological and cultural significance.
“Following requests for such agreements from Cyprus and China, the government in 2007 and 2009, respectively, restricted the import of ancient coins minted in those countries.”
After customs agents seized a consignment of ancient coins originating within the borders of the two countries, the Ancient Coin Collectors Guild filed a challenge to the regulations.
According to the guild’s complaint, the U.S. government was unreasonable to seize the coins absent any evidence that any link in the coins’ chain of ownership resulted from force or fraud.
But it’s hard to win a challenge to government action under the New Deal-era “rational-basis” test, and a federal judge just dismissed the case.
Over the past few decades, the development of international antiquities law has led to demands for the repatriation (as it’s called) of artifacts large and small from both museums and private hands.
Peru is suing Yale for the return of Machu Picchu ruins; Greece wants the Elgin Marbles back; Egypt is demanding the Rosetta Stone and a famous bust of Nefertiti.
Similarly, domestic laws banning trade in pre-Columbian and indigenous remains and artifacts have closed down ever-wider swaths of collector activity.
Much of this new body of law rests on the dubious premise that cultural artifacts of great antiquity, even those that have been in the hands of Western museums or collectors for hundreds of years, should by right be subject to the dictates of whichever national government or sovereign entity happens to lay claim to the territory where the objects were originally crafted.
Such national governments, however, are often culturally quite distinct from the civilizations that inhabited those places over millennia, and often lack either the will or the means to conserve fragile artifacts as well as collectors would. The fate of more than a few “returned” artifacts has been to get stolen or to crumble in the hands of inexpert new custodians.
Is some sort of property right at issue? Well, one might conceivably argue that certain artifacts, such as funerary urns and temple friezes, must by their nature be regarded as stolen property since at some point they must have been looted from sites originally contemplated as permanent.
However, temples might choose to sell their friezes, dynasties go out of business with no receiver in bankruptcy and so forth.
But coins are just the opposite. They were meant to circulate and, if of good value, they might soon be found in intended and legitimate use far from their country of origin.
Much of the success of coins as an institution in economic history (as with precious metals more generally) arose from their very anonymity, the fact that when they changed hands they left no paper trail for a jealous sovereign to trace.
Yet modern antiquities law falls over itself to cater to the wishes of the jealous sovereign, at a cost to both fairness and the interests of conservation. Why?