You can if the manufacturer has a track record that refutes the notion, and especially if they have verifiable hardware matching publicly disclosed circuit designs. But this is Intel, with their track record, I wouldn't trust it even if the schematics were public. Intel ME not being disable-able by consumers, while being entirely omitted for certain classes of government buyers tells me everything I need to know.

> That's my point, this sounds like a way to create a backdoor for at-rest data.

I get the feeling honestly it seems more expensive and more effort to backdoor it..