Recently the U.S. customs started a large-scale sampling inspection work for amazon goods. The inspection is mainly for goods declared under $800 whose weight is over 100KG. At present, it mainly exists center on the transit site like Louisville, KY.
It says that U.S. customs would enlarge inspection work 100% for goods declared under $800 across the whole region in the US. Currently the UPS has begun to dispatch with a delay or to detain goods at the warehouse whose declared value is under $800.
YCD suggests declaring the name, quantity, HS code, brand name if there is and the value on the invoice truthfully.
At present if there is no any problem with the goods, it can be resolved simply by providing information (BOND etc) of the American importer. UPS would contact the importer to verify the value of the goods, and keep the right to collect custom duties