The U.S. government agencies that watch over any threats would rely on ship manifests and intelligence to hopefully secure our borders. Certain things would not be allowed into our country say like surplus RPG's,grenades,and such. It's where these shipments are being distributed to. You can't even buy more than three packages of sudafed without someone knowing. The 1099 forms insure than nothing is done in a big way without Big Brother knowing about it. Anything that can be used in a government takedown is heavily regulated.
But,that's just my opinion.
But,that's just my opinion.