The "background check" requirement protects the seller.....just as it would protect a "private" seller if he/she required it for a private sale.  I fear we will read of a very sad case of an Oregon individual selling a gun in a private sale w/o requiring a background check and then, the buyer (who would NOT have passed that background check)  uses the weapon to commit a serious crime...perhaps killing someone.  If that happens, and surely it might, I'm guessing THAT particular seller will be facing civil and possible criminal jeopardy.  For my own protection, I would NEVER sell a firearm w/o that background check.  I'd like to hear from some "gun guys" on this one.  Gary Crum