What reason is there for Sasori to put a spy on Orochimaru other than him being an Akatsuki traitor. Aren't they too hunting him down trying to kill him. I have to give Oro credit though not only is he a S rank missing-nin who is wanted in most if not all the villages for death but even an organization made up solely of S rank missing-nin is hunting him and he still manages to escape them all. That is how you know you're a badass when even the bad guys want to kill you.