Gunwalker was used by the Bush administration, where they actually did their jobs and arrested the straw purchasers.
It was called Gunrunner at that time. They did not let the guns “Walk”.
The Bush version of Gunrunner included the imperative NOBODY GOES HOME UNTIL THOSE GUNS ARE SEIZED. Risky, but workable.
That is very different from “make the illegal sale, go home, and wait for the serial number to show up somewhere.”