All or Rin’s slaves serve her dutifully and without an ounce of fight in them. And while Cloud does go against the grain by interacting with Morrigan behind the back of her mistress, she serves Rin with no objection. Yagami managed to escape and Ivy managed to buy herself into freedom, but even they could not technically be called spies because neither were conspiring against her while in captivity.

As an aside I saw one of those top boobjob gifs on my server and I felt like I should give it a try…