Are Placebos Fraud?

This is a conundrum I have been struggling with. There is such a thing as the placebo effect, but it is dependent on deception. Normally deception would mean fraud, but this would exclude a possibly effective treatment. I don't see how anybody would sign a contract with a doctor, which includes as part of it that one may be deceived at the doctors discretion. So without such a clause, wouldn't a prescription of placebos or homeopathic "medicine" constitute fraud?

How do placebos fit into a voluntarist framework?