Gun and knife shows are well regulated and closely watched. Each gun vendor must have a federal firearms permit which requires that every handgun transaction be recorded with names, addresses, purchase permit numbers, etc. While technically true that these shows put more guns "on the streets", the hands in which those guns are placed are by vast majority of law abiding citizens. Guns, like drugs, have a huge black market and are much more readily available through illegal channels than gun and knife shows.
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