Continuity mistake: Just after the other group of men say "Go easy on him, Sarge. That's the Prime Commander's son right there." 'Sarge' turns his head back to face the boy and has his head level, not moving. It cuts to a frontal view and suddenly his head is tilted to the right and moving around. (00:12:45)
Continuity mistake: Approximately two scenes after Kitai leaves the pigs' burrow where he sheltered for the night, the "cutlass" is suddenly missing from his backpack. He later retrieves another from the ship's tail section. There is likely a deleted scene which would have explained the loss of the cutlass.
Answer: Probably because it wouldn't work. On "Mythbusters," Adam and Jamie tested whether a tracking dog could still trace a human clad in a hermetically-sealed suit to contain the scent. The dog easily tracked Jamie.
raywest ★