That is why they want to close the "gun show loophole." When possible, I prefer to find the private collections at gun shows and pay cash. They are just fewer and further between.
You mean like photographing every piece of mail they handle?
WASHINGTON — The Postal Service on Friday confirmed that it takes a photograph of every letter and package mailed in the United States — about 160 billion pieces last year — and occasionally provides the photos to law enforcement agencies that request them as part of criminal cases.