Wrong. ANY SALE made by a dealer must have a background check.
A private citizen may make sales of personal property that do not constitute ‘engaging in business’ without a license. Typically, people are selling used guns so they can upgrade, or an old collectible or inherited piece.
This is true anywhere — flea market, garage sale, classified ad, friend’s house, gun show.
The law is EXACTLY THE SAME in or out of a gun show.
If you believe otherwise, cite the law that says, “you can do this at a gun show but not anywhere else.”
I’ll wait.
Beyond that — no manufacturer or distributor legally can or will sell guns to someone who does not have an FFL — a license to be a dealer. So it’s pretty much impossible to engage in the business of selling them, since you can’t get a wholesale source.