If it is only slightly over the $800, say only a few hundred over, the CBP examining you might decide that it is not worth the time and hassle just to collect a few dollars in duty.

I once brought in some gifts with a total value over the personal exemption, and when I declared as such to the CBP officer and asked where to go to pay the duty, he said: "It's not worth 20 minutes of my time doing paperwork to collect about 4 dollars from you. Have a good day."

The U.S. import duty laws are more intended to be applied to commercial importers bringing in extremely large quantities / high values destined for resale in the United States. When someone is bringing in $5 million worth of foreign merchandise to be sold domestically, Uncle Sam understandably wants to take a healthy cut for the government.

That said, please keep in mind that it is VERY important to declare all merchandise that you are bringing into the USA of foreign source(s). Not to do so could risk heavy fines (far more than you would owe in duty for personal goods) and, perhaps even worse, flags on your CBP record that could make future entries to the country very inconvenient for a lengthy time in the future.