Law's do not prevent crime.

I can understand regulating gun shows such as requiring vendors to have licenses and tracking all sales. The vendors will complain at first, but I don't think this would stop gun shows, as long as there is money to be made for the vendors. But, you're not going to be able to control individuals selling guns to other individuals. That's too big for big brother to handle. He can't even get a handle on the illegal alien problem.