leo has no memory, but if you remember, there was the scene with the sammy jenkis being tested for some kind of unconsciously induced memory, the scene where he gets shocked repeatedly for picking up the wrong block. well they said most patients with short term memory loss, do eventually stop picking up the shock block, which suggests some type of vague notion of memory induced by stimuli or repitition. so we can assume that leo unconsciously remebers to check hi spockets from repitition.
but anyways even if my counter-theory is flawed, have you ever seen a perfect movie? i agree with k-katherine, dissection of logistics is fun, but it gets old.