The prosecution rates for violations of the existing BGC are extremely low. I can only imagine that it would become even lower if expanded BGCs were expanded to include private sales. And if some individuals ignore the BGC, is an already overworked prosecutor likely to bring charges to those individuals if they are not prohibited persons?
First, there's a tangle of words here, we must untangle.
"violation of existing BGC" is not quite what is sounds like. And, I am in a place where BGC on ALL private transfers is the law. What violation of the BGC law means is not running the check at all. It does not mean "failing" the check. No matter what the check results are, running the check is compliance with the law. Period.
(and, where I am, not getting the check done is a misdemeanor, the first time...)
Now, someone LYING on the 4473 (in hope of passing the check) IS a crime, and it is a separate crime from not having the check run.
How likely are prosecutors to bring charges? VERY likely to add gun control law violations to the list of charges when another crime is the major one. Also very likely to "throw away" those charges as part of a plea bargain deal.
Very rare for prosecutors to do more than just bring the charges to use as a threat. Actual prosecutions as a stand alone crime are very seldom done.
And here's another tidbit to consider, you cannot bring charges against a felon/prohibited person for failing to register a gun. This is established law. I don't think we have a ruling on BGC laws about that, yet, but I expect them to be in line with established law when/if they are made.
Simply put, registering a gun (and perhaps going through the BGC??) violates the prohibited person's civil rights. (5th Amendment). You can charge them with illegal possession of a gun, but you cannot charge them with failure to comply with registration laws.
If I were a an FFL dealer, with a commercial storefront operation, I would be a HUGE supporter of mandatory background checks on all transfers. It's a guaran-fracking-teed income stream, by LAW!!!
Since I'm not an FFL dealer, and BGCs cost me money rather than making me money, I oppose them.
We've established pretty solidly (I think) that a background check cannot stop someone who it not already a prohibited person. And that they do not stop a few people who are prohibited persons but are not in the system as such, due to some reporting failure.
And that the oft repeated mantra of "keeping guns from the hands of people who shouldn't have guns" is entirely a moot point if a person already has a gun (ANY gun).
How's this for a compromise, take the check
OR show the seller proof you already own a gun. because if you already have a gun, the check is worthless, and does not, cannot, and will not do anything useful to prevent criminal conduct.