Smith was sinbinned for the role he played in a tackle on Blues replacement halfback Tony Morland in the 76th minute of the Highlanders' 15-10 loss at Carisbrook on Friday night.
Sanzar judicial officer Nigel Hampton QC, after hearing evidence, found that the citing could not be made because Smith was not the player primarily responsible for lifting and then dropping or driving Morland to the ground.
Hampton, who viewed additional video evidence concluded that another Highlanders player involved in the tackle had played the dominant role in lifting and dropping Morland.