I used to wonder what consciousness could be, until you all shared its qualia with me.

You know, we could simply ask; "What would convince us that the simulated humans are not conscious?" "What would convince us that we ourselves are not conscious?" Because, otherwise, "unconscious homunculi" are basically the same as P-Zombies, and we're making a useless distinction.

Nevertheless, it is possible for a machine to be mistaken about being conscious. Make it un-conscious (in some meaningful way), but make it unable to distinguish conscious from unconscious, and bias its judgment towards qualifying itself as conscious. Basically, the "mistake" would be in its definition of consciousness.