Even though the Lamanites had become more cautious about possible tricks, their scouts report a comparatively weak but complete army encamped near them and scent an easy victory. Concerned about the possible disruption of their supply trains, they consider Helaman’s approach as just one more tactical sally, but on a larger scale. Given their numerical superiority, they calculate that they can destroy Helaman’s army so thoroughly that they would assure a final victory in this region.
The reason that the Nephite strategy works is that Gid and Teomner depart with their men only after the Lamanite spies have reported the troop strength. Thus, the Lamanites have no hint of an ambush because they think they can account for Helaman’s entire army.