As the Wall Street Journal Legal Blog observes,
"The next time you try to bring antiques into the U.S., think again: if they look old enough and don�t have any documentation, customs officials might just seize them as potentially looted cultural artifacts."
http://blogs.wsj.com/law/2011/08/15/court-rules-u-s-customs-rightfully-seized-ancient-coins/?mod=google_news_blog
Scare tactics? Hardly. It's not too hard to imagine someone purchasing an old Roman Republican coin at a shop in Italy or one of the millions of Chinese cash coins extant at a stall in Indonesia, only to have it seized by those ever so friendly US Customs officers after a long flight at the end of what had beforehand been a pleasant vacation.
Perhaps the bureaucracy is out of control after all....even if at least one US District Court Judge would rather not hold it accountable as a legal matter.