Come on, get a grip FFLs rather than start counting your increased fees ....
A few months after the Washington universal background check infringement was passed by the public paid off by Bloomberg, I asked a local FFL how much business he has made from private sales. He said none. Those few people who have come in and asked about it, he has told them that the no law enforcement agency in the state is going to enforce the background check law until the gun is transferred to somebody that commits a crime with it and that the local police chief has expressed, in person, that he won't enforce the law. So most people who want to sell a gun to someone they know is just doing it without the background check anyway, in Washington State.
Further proof of this law not being enforced in Washington state is the fact that 1,000's of retail sporting goods and marine stores are selling firearms every day without the required background check, at retail, and not a single prosecuting attorney in the state is willing to do anything to enforce the stupid law. According to Washington state law, flare guns are pistols. Since they are not classified as firearms according to Federal law, no FFL and background check was required for Wal Mart to sell them. However the state background check law does require them to go through an FFL and background check - but I don't know a single store that sells flare guns that is complying with the law because nobody in this state has any interest in enforcing the law.
And that's how universal background check laws work - just like the 1000' School Zone victim zones. They don't stop criminals.