You can obviously sell to whom you want. In the end it's you that are gonna explain to the Po-po somewhere how your gun that got used in some crime was sold off and you don't have no BOS or nothing to show for it...
Huh? The burden is not on you to do that level of ‘splainin. GA law enforcement knows how private sales work in the state. I’ve done at least half a dozen deals with LEO, in squad cars and all. Hell I even bought a Keltec PF9 off a local DA once. Never any mention of a BoS. There is absolutely nothing a BOS does to exonerate you from any potential “crime” or whatever you have in your mind. It’s literally just a piece of paper with some notes on it. Not notarized, not official, easily forged.
I also once thought a BoS was a good way to CYA but it’s completely useless. If authorities want to know who you sold/bought a gun from online, it’s easy to trace. No hiding it even if you wanted to, unless you’re going to great lengths to be incognito.