First, they are imperative sentences (commands). I think your paraphrases are right; here are mine: Lock out thieves in the night - - Lock out thieves during the night Lock out thieves in the light -- Lock out thieves during the daytime Lock out thieves out of sight -- Keep thieves so far away that I cannot see them. (For the rhythm of the chant, an extra 'out' has been added, of course.
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