The purchase by gift card proves the receiver of the gift card was not in profit-making mode (hence no fed or state income taxation); and the giver of the gift card (and new possesser of the gun) is not subject to sales tax. IIRC
Remember, we're now talking of maybe a few hundred dollars of value -- and if no exchange, the gift cards can still be used to buy something else.
De-commercializing the exchange. Hence no state tax number, no FFL required. Just slicker than frog's hair!
It's going to be very important to defeat the call for universal NIC checks -- because what they really want to do is run a sub-rosa, lefthanded-bastard national registry, as a tool for confiscation (presumably by weapons classes parted out and prioritized by "scariness").