God should have known better than let Joseph let Martin borrow it. He did. Martin was repeatedly told "no". But, as God is wont to do, when people pester Him enough, sometimes He relents in order to teach a lesson.
What lesson did LDS god give Prophet Joseph? The lesson his SEER didn't foreSEE what would happen to them? Sure looks like a alibi in case these 116 pages were to turn up?