@highaccuser: It's not about living, Raiden is very clearly alive. It's about being organic and possessing chakra. Since when is chakra not required in order to use a technique that blocks your chakra channels?
Pain clearly wasn't organic but he had Chakra. And it's not really clear how it works but people were put under Genjutsu before Chakra was dispersed amongst them. It doesn't make much sense but there you go.
Anyway this doesn't matter much since Genjutsu would work on Sam regardless.