Name a single shooting AT at gunshow.
One person murdered at a gunshow will suffice.
I don't think such exists because we'd be hearing about it every day to justify closing the "loophole".
Of note is most gunshows here in Florida are gun-free zones. No loaded weapons allowed, even for those with toter's permits.
It's a ridiculous rule, how long do you think it would take you to get what you needed to get into action?
And that's why there's never a shooting at a gun show. Ten seconds after that shot the whole place would have that zip tie cut and a round chambered.