I'd challenge anyone to come up with even anecdotal evidence that gun shows are a significant source for crime guns.
Lanza didn't buy one there. Cho, Loughner, Holmes, and the others didn't buy one there.
Folks, gun shows and private sales are simply not a big enough problem that they need to be regulated. Asking for more restrictions, no matter how "harmless" they may seem, is a slippery slope.
Sometimes it’s nice not to destroy the world for a change.