An article in today's New York Times suggests that the Southern California antiquities scandal may really be about the sale of tax deductions:
"Applications for the warrants said under the scheme, that smugglers and art dealers were selling prehistoric artifacts to Americans, who were provided with inflated appraisals. Then the art dealers arranged for the items to be donated to the museums, so the donors could take a tax deduction. ... According to the warrants, many of the artifacts were sold to the donors for around $1,500 each and then appraised at prices just shy of $5,000. (Above that amount the paperwork requirements on a tax return grow stiffer.) For a taxpayer in the maximum tax bracket, the savings would be only about $700 a piece."
$700 seems a tad low, but in the right ballpark. The mention of "stiffer paperwork requirements" is a reference to the fact that it's at $5,000 that the need for a "qualified appraisal" kicks in. See IRS Form 8283.