Board Thread:Naruto Discussions/@comment-2245550-20160501143136/@comment-2245550-20160503100744

Regular Uchiha can use Izanagi. That's evidential by Madara faking his own death by using it, and also by the Uchiha abusing Izanagi in their multiple quests for power over the clan.

Orochimaru wasn't aware of that. If he were, he'd have put Hashirama's cells into Shin, which he obviously didn't. Sure, he gave Danzo cells of Hashirama, but they weren't given through Shin's arm.

You said they were aware of almost everything he's done, which leaves space for Madara taking Hashirama's flesh. If he and Orochimaru were aware that combining Uchiha and Senju DNA would bring forth the Rinnegan, they'd have already had it by now.

At any case, this is all besides the point. Back to the main question: Is Orochimaru arrogant/confident enough in himself that he'd think there's no way his plans could go wrong and wouldn't use any sort of precautions just in case?