When I was buying my Beretta CX-4 Storm, I asked about the PICS check on rifles, because, as I mentioned, when private individuals sold them there was no legal requirement for such checks.
An old guy behind the counter said: "You got your information wrong, buddy."
After a moment of shock (because how does an experienced man who works behind a gun counter NOT know this?), I merely replied: "Not at all, I'm very sure of it and as a matter of fact, there was a big discussion on a recent internet board where I read all the laws myself."
He then said: "Well, I guess that's the 'gun show' loophole. You can bet that they're going to change that soon."
(here's my face after hearing that)
Anyway, the point is, nowadays, not even those you would expect to know something know something.