Am I missing something or is this just an invitation for people to do more horse trading when selling a gun?
Like MechAg said, the new rule explicitly covers horse-trading. Honestly someone I didn't know offering something other than cash for a gun (especially at a gun show) would set off more red flags for me. Either prohibited person/snitch or Fed looking to make a deal that will seem shady to a jury of normies.
Much safer for them to go after people selling their collection that Tyrone with 15 Glocks with switches and fun sticks in the trunk of his Impala.