I don't disagree with this at all, but to be clear the issue isn't necessarily gun shows (the "gun show loophole" gets thrown around a lot). The problem you're talking about is private party sales, which can happen anywhere (yes, gun shows are a popular place to do this). I have a shotgun in my safe I bought at a garage sale.I am pro 2A but people should not be able to buy guns (normally this happens at gun shows) without any paper trail.
Any dealer at a gun show is required to follow the same process as they would if you walked into their shop. I'm sure you know all of this, but many seem to use gun shows as the actual issue.