The lay crowd doesn't have time/experience/inclination to understand the minutia, that's why they defer to the specialist.

Therefore it is always the responsibility of the specialist to communicate necessary information in a way that's generally understandable. Since their definition of 'basic understanding' will never match yours, you should be prepared to explain each necessary component from the ground up until they can understand the issue at hand.

And the lay are perfectly justified in asking questions/making suggestions even if they don't have the first clue what the implications of their suggestions are.

Because suggestions should be treated purely on merit, not source. If the receptionist asks "Raid 0?" your answer should be as tactful, careful and considered as if the smartest geek you know had said it.

Much of the rest of your comment deals more with 'playing well with others', rather than communication itself.

Lay people dictating technical solutions despite warnings from their specialists isn't miscommunication; it's someone being a shortsighted, micromanaging dick.